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INTEGRAL Science Data Centre IBIS Analysis User Manual

1. E_MIN Lower bound of the energy range ID IE PD PE E_MAX Upper bound of the energy range ID IE PD PE BANDTYPE Type of energy band ID IE HIS_TYPE Type of histogram data PD SHD_TYPE Shadowgram type PE C 5 cat_extract The catalogue extraction selects the sources in the FOV from the reference catalogue The output Data Structures ISGR SRCL CAT and PICS SRCL CAT have the same structure as the reference catalogue GNRL REFR CAT see Table 48 Table 48 Content of GNRL REFR CAT Data Structures Column Name Description SOURCE_ID ISDC unique source identifier ISDC IBIS Analysis User Manual Issue 5 1 91 DAY ID Modified Julian Date of source s first identification NAME One commonly used name for the source CLASS source classification code RA OBJ Source right ascension in degrees DEC OBJ Source declination in degrees ERR RAD Error radius SPA MODL Model for source spatial extension point disk ellipse square gaussian Bspline etc SPA_NPAR Number of parameters for source spatial extension SPA_PARS Parameters for source spatial extension SPE MODL Model for source spectrum XSPEC syntax SPE NPAR Number of parameters for source spectrum SPE PARS Parameters for source spectrum VAR MODL Model for source intensity variability constant sin burst VAR NPAR Number of parameters for source intensity variability VAR PARS Parameters for source intensity variability COMMEN
2. 12 8 2 sumhist PICsIT needs long integration times to produce a good image Thus if INTEGRAL was stable during several Science Windows it is recommended to sum up PICsIT shadowgrams before the deconvolution If the ibis_science_analysis parameter staring is set to yes then sumhist checks that INTEGRAL was stable during all the Science Windows within the given limits and sums all the PICsIT shadowgrams into one Table 19 sumhist parameters included into the main script Name Name Type Description in the main script executable tolerance tol real tolerance for staring default 0 0001 12 8 3 ip_skyimage ip skyimage performs deconvolution of the shadowgrams with the use of the balanced cross correlation method described above for more detailed explanations see Goldwurm et al 2003 10 The weighting array W corresponds to the efficiency map The values of the decoding G array are taken from the IC file The ip_skyimage parameters included into the main script are given in the Table 20 Table 20 p_skyimage parameters included into the main script Name Name Type Description in the main script executable PICSIT det Thr detThr real Detection threshold for the automatic source location PICSIT inCorVar inCorVar integer Corrected variance to be used 0 NO 1 YES PICSIT_outVarian outVarian integer Variance maps in output 0O NO 1 YES PICSIT_deco maskDeco string DOL of the deco
3. Parameters specific to SCW1 pipeline SCW1_ISGRL event_select string CFITSIO event selection string default gt SCWI1 GTI Limit Table string DOL of the limit table for GTIs default gt SCWI1 GTIatt Tolerance real Accepted attitude variability arc min possible values 0 180 0 default 0 5 SCWI1 GTI gtiUserP string DOL of the user GTI table for PICsIT default SCWI1 GTI gtiUserI string DOL of the user GTI table for ISGRI default SCWI1 GTI TimeFormat string Time format to be used possible values IJD UTC OBT default IJD SCW1_GTL Accuracy string Used accuracy for OBT to IJD conversion and vice versa possible values any inaccurate accurate default any ISDC IBIS Analysis User Manual Issue 5 1 101 SCW1_GTISCP SCW1_GTLSCI SCWI1 GTI PICsIT SCW1_GTLISGRI SCWI1 GTI BTI Dol SCWI1 GTI BTI Names SCWI1 ICOR idxSwitch SCWI1 ICOR GODOL SCW1ICOR riseDOL SCW1ICORicDOL SCW1_ICOR_probShot SCW1_PCOR_enerDOL SCW1_BIN_cleanTrk SCW1_veto_mod SCW1_BIN_LidxNoisy SCW1_BIN LidxLowThre SCW1_BIN_P_inDead string string string string string string string string string string real string integer string string string string Names of spacecraft GTIs to be merged for PICsIT default gt Names of spacecraft GTIs to b
4. 1 Dead Time i Event Binning for Image BIN I ibis binning Binned Events a i 1 a Background Correction BKG Ee onam con j Rebinned Bckg and Efiiciency Shadowgrams i 7 c m Shadowgrams Corrected for Background ibis obs1 analysis pe ccc CRURA CE EET cat extract i Catalog Source Selection CAT I Lalo LL List of Sources in FOV T 1 ISGRI and PICsIT staring IMA a i a Image Reconstruction nM ii L ISGRI and PICsIT staring o Images ibis scw2 analysis T oe EU UL upon 1 PICsIT Image Reconstruction IMA2 ip_skyimage _ PICsIT Images P i mii map rebin i Event Binning for Spectra i ibis_binning 1 I Events Binned l BIN_S i for spectra extraction i ibis backgrmund cor gt E 1 4 1 u Spectra Extraction SPE li spectra extract ISGRI spectra 1 tg i Helens iM EE 7 ip Stc extract Lighteurve of PICsIT 3 LCR 1 Spectral Timing Data tesi Cighteurve creation i ii lc_exctract ISGRI source lightcurves ibis_obs2_analysis panne porns o M 2 gt 1 Summing of the results 1 CLEAN ip skymosaic PICsIT mosaic Figure 10 Science Analysis Overview For the time being Compton analysis is not available ISDC IBIS Analysis User Manual Issue 5 1 15 e The first script bis_scw1_analysis performs the following tasks COR Data Correction Tags noisy pixels corrects energy of the photons for rise time and temporal vari
5. 2 PKsIT multiple an PR ISGRI PICsf t EE gt r y oonl s O ey eer oer aw S M CONES t E CRDI V 10 100 1000 TOC Energy kev Figure 9 IBIS sensitivities for the various detection techniques 4 2 IBIS observing modes IBIS has several observing modes for engineering and calibration purposes However for scientific use there is only one operating mode Science Mode In Science Mode ISGRI registers and transmits events on a photon by photon basis i e every event is tagged with X Y position on the detector plane event energy from the pulse height and rise time and event time PICSIT in principle can also operate in photon by photon mode However with the higher background compared to ISGRI there would be unacceptable data loss Therefore the standard mode for PICSIT is histogram Images and spectra full spatial resolution 256 energy channels are accumulated for about 30 minutes before transmission to ground There is no time tagging internal to the histogram i e spectral imaging has time resolution of 30 minutes In addition coarse spectra without imaging information are accumulated by PICSIT and transmitted with far higher time resolution but without imaging information Thus their usefulness is limited to observations of very strong sources where the source countrate dominates the background The time resolution and the number of energy channels for this spectral timing
6. X Per usrcat fits chmod w usrcat fits If you want to add a new source not specified in the general reference catalog add a line to usrcat fits with the help of the fv tool and fill in the Source ID NAME RA_OBJ and DEC_OBJ columns As Source_ID you can choose whatever you like provided that this identifier is unique NOTE usrcat fits keeps the same format of the general reference catalog from which it was built i e it has the extension of the type GNRL REFR CAT This is the correct extension to be used as input for the Imaging step In Section 7 2 you have been shown how to build a catalogue for the lightcurve LCR and spectral SPE step In that case the catalogue you obtained specat fits was of the type of ISGR SRCL RES which is the correct format for the LCR and SPE steps The two formats cannot be switched meaning that you cannot use a GNRL REFR CAT type catalog for SPE and LCR or an ISGR SRCL RES one for IMA 9 7 Alternative Spectral Extraction from the Mosaic Read this if you want to extract the average spectrum of a source from a set of mosaic images in different energy bands It is possible to extract the spectrum of a source from a set of mosaic images in several large energy bands In general this method gives results similar to the Science Window average spectrum you obtain from spe_pick see Sections 7 2 and 9 3 2 Once you have the spectrum you will need the corresponding rebinned matrix to b
7. shadowgrams are simulated default 0 ISDC IBIS Analysis User Manual Issue 5 1 75 OBS1_SearchMode OBS1_ToSearch OBS1_CleanMode OBSI tungAtt OBSI aluAtt OBSI leadAtt OBS1_ScwType OBS1_DoPart2 OBS1_MapAlpha OBS1_MapDelta OBS1_MapSize OBSI PixSpread OBS1_MinCatSouSnr OBS1_MinNewSouSnr OBS1_SouFit SearchMode ToSearch CleanMode tungAtt aluAtt leadAtt ScwType DoPart2 MapAlpha MapDelta MapSize PixSpread MinCatSouSnr MinNewSouSnr SouFit integer integer integer string string string string integer real real real integer real real integer ISDC IBIS Analysis User Manual Issue 5 1 Source search mode possible values O search for all significant excesses 1 search for all catalog sources 2 search for K sources where K ToSearch 3 search for all catalog sources plus K significant excesses where K ToSearch Parameter SearchMode 1 3 concerns only images at a Science Window level In the mosaic image ii skyimage always looks for K ToSearch sources default 2 Number of sources to be looked for default 15 Ghost cleaning possible values 1 source model lobes are subtracted from the decon volved image 1 no subtraction default 1 DOL of the Tungsten attenuation length fits file default gt DOL of the Aluminium attenuation length fits file default DOL of the L
8. Issue 5 1 74 Then the source contribution to the image is modeled in detail and subtracted The images are rotated projected and summed after being weighted with the variance and then searched for further contributions More details can be found in 8 9 12 8 1 ii skyimage ii skyimage deconvolves shadowgrams in the given energy bands for each Science Window using the balanced cross correlation method described above The energy bands should be either the same as in the ibis binning or the bands created by the merger of those bands The deconvolution is weighted by efficiency Thus the weighting array W contains efficiency for normal pixels and 0 elsewhere A search for sources is performed in the deconvolved image The list of sources found is created and the images are cleaned from the PSF ghosts In the deconvolved image the pixel value at the source position is the total source flux in cts sec units It is calculated as if the source was in the fully coded field of view FCFOV One should NOT do any integration in the source region to estimate the flux from the image The source flux estimation given in the source list is slightly different as the source flux is given at the fitted source position For each output energy band all images of the same type are combined into one mosaic image A search for the sources in the mosaic image is then performed and a list of sources found is created The current version of software allows
9. St anc IBIS Analysis User Manual ISDC mse 17 November 2005 5 1 ISDC OSA UM IBIS INTEGRAL Science Data Centre IBIS ANALYSIS USER MANUAL Reference ISDC OSA UM IBIS Issue 5 1 Date f 17 November 2005 INTEGRAL Science Data Centre Chemin d cogia 16 CH 1290 Versoix Switzerland http isdc unige ch Authors and Approvals Se ISDC IBIS Analysis User Manual AIN 17 November 2005 5 1 Prepared by M Chernyakova Agreed by Ret Walter aet gs la et eere A AA sd Approved by D COUrvolsieE aa A A ada ISDC IBIS Analysis User Manual Issue 5 1 i Document Status Sheet dT ISDC S IBIS Analysis User Manual 2 April 2003 1 0 First Release 19 May 2003 1 1 Update of the First Release Section 6 Tables 61 9 11 12 15 50 56 and Figures 10 28 were updated Section 12 9 1 was added 18 July 2003 2 0 Second Release Sections 5 6 8 and the bibliography were updated Sections 12 9 12 12 2 C 8 C 9 2 were added 5 December 2003 3 0 Third Release Sections 6 7 and 8 were updated Sections 9 10 C 9 3 were added 19 July 2004 4 0 Fourth Release Sections 6 7 8 and the bibliography were updated 6 December 2004 4 2 Update of the Fourth Release Sections 6 8 Tables 15 16 and the bibliography were updated 29 June 2005 5 0 Fifth Release Cookbook Part was completely rewritten All other parts were updated 10 August 2005 5 01 Minor update of t
10. 7 OBS1_SouFit integer defines whether to fit or not the source position 0 for fitting source position in Scw fit 1 for fixed source position in Sew fit default 0 PICSIT_detThr real Detection Threshold default 3 0 ISDC IBIS Analysis User Manual Issue 5 1 105 PICSIT_inCor Var PICSIT_out Varian integer integer Corrected variance to be used 0 NO 1 YES default 1 Variance maps in output 0 NO 1 YES default 0 cat_extract parameters see Section 12 7 for more details OBS1_CAT_radiusMin OBS1_CAT radiusMax OBS1_CAT fluxDef OBS1_CAT fluxMin OBS1_CAT fluxMax OBS1 CAT class OBS1_CAT date string string string string string string real Low limit for the position selection default 0 High 1 default imit for the position selection ec 20 22 Column used for flux selection default Low limit for flux selection default High limit for flux selection default gt Select the object by class default IJD for the public data default 1 Parameters specific to SCW2 pipeline PICSIT deco SCWA2 cat for extract SCW2 racolumn SCW2_deccolumn SCW2_catalog SCW2_PIF filter SCW2_ISGRI event select string string string string string string string DOL of the MASK decoding fits file default Catalog for spectral and lightcurve extraction if
11. 9 T 9 8 9 9 Retunning the Analysis 2 44 5 22r x o o RR Ros RR UR a Make your own Good Time Intervals o Combining results from different observation groups 9 8 1 Creating a mosaic from different observation groups 9 3 2 Combining spectra and lightcurves from different observation groups Rebinning the Response Matrix oe Ge ce e Rn 9 4 1 Extracting images in more than 10 energy ranges cen Some tricks on saving disk space and CPU time e Croate your B CALLE uuu 64 ko AA EEE ed Oe Ee ERE ow Alternative Spectral Extraction from the Mosaic o e Bervyeentrisaion 2 0 22 566 es e AA o Re eee Eee doy v Alternativo Timing Analysis 2 se AA A RRS Se Oe ER ES e s 9 9 1 i3 EHE aa Re ee Pee RRR et ed ee eee ud 9 9 2 Bn e rca a AA A od 9 9 3 Merge the ii_light results from different Science Windows ISDC IBIS Analysis User Manual Issue 5 1 42 43 43 44 44 45 45 45 46 46 lv 9 10 Timing Analysis without the deconvolution o o e e 47 10 PICSIT dats analysis co cores ear a aia a 48 10 1 PICIT Image Reconstruction 2 o c Lee a a eee GOED ES 49 10 1 1 Results of PICsIT image analysis eee 52 10 2 PICsIT spectral extraction from the mosaic image llle 52 10 3 PICsIT pipeline spectral extraction ee 54 10 3 1 Displaying the results of PICsIT spectral
12. B 1 Noisy Pixels It is possible that with time some of the pixels of the detector start to produce an output not triggered by an income photon i e to become noisy If the particular pixel countrate is too high relatively to the module countrate then the on board electronics switch it off In ISGRI the noisy pixels can recover after being switched off for some time and disabled pixels are periodically reset to check their status Data Structure ISGR SWIT STA with the list of noisy pixel switches in the ISGRI detector layer is produced during the pre processing basing on the rise time information and pixels light curves transmitted see Table 31 Table 31 Content of ISGR SWIT STA Data Structure Column Name Description ISGRLY Y location in the ISGRI layer ISGRLZ Z location in the ISGRI layer OBT DETECT First time when the pixel can be declared as noisy OBT SWITCH OBT when the pixel is switched off NOIS FLAG Noisy flag In PICsIT pixels cannot be recovered that easy A PICSIT pixel will remain off once killed Only if half of the detector or so will be off pixels will be attempted to turn on The history of the disable pixels can be found in Data Structure PICS FALT STA see Table 32 Table 32 Content of PICS FALT STA Data Structure Column Name Description PICSIT Y Y location in the PICSIT layer PICSIT_Z Z location in the PICsIT layer OBT_DETECT First Time when the pixel can be declared as noisy
13. COR to DEAD level prepare the catalog with Crab only and run Zi pif cd REP BASE PROD obs crab ibis science analysis ogDOL og_ibis fits 1 startLevel COR endLevel DEAD fcopy infile ISDC REF CAT NAME Crab outfile crab_specat fits ii pif in0G outO0G og ibis fits 1 inCat crab_specat fits 1 num band 1 E band min 20 E band max 1000 N mask 1SDC IC TREE ic ibis mod isgr mask mod 0003 fits 1 N tungAtt l1SDC IC TREE ic ibis mod isgr attn mod 0007 fits 1 N aluAtt ISDC_IC_TREE ic ibis mod isgr_attn_mod_0008 fits 1 leadAtt ISDC_IC_TREE ic ibis mod isgr_attn_mod_0009 fits 1 Now you are ready to create the lists of photons ISDC IBIS Analysis User Manual Issue 5 1 47 cd REP_BASE_PROD obs crab evts extract group og ibis fits 1 events crabevts fits instrument IBIS sources crab_specat fits 1 gtiname MERGED_ISGRI pif yes deadc yes attach no barycenter 1 timeformat 0 instmod To increase signal to noise ratio select only events with PIF 1 fcopy crabevts fits 2 PIF_1 1 crab_pif1 fits chmod w crab_pif1 fits Now you can produce the Crab power spectrum powspec Ser 1 filename options or file of filenames options crab pifi fits Name of the window file for default window Newbin Time or negative rebinning 0 001 Number of Newbins Interval INDEF Number of Intervals Frame INDEF Rebin results gt 1 const rebin lt 1 geom reb
14. ISDC IBIS Analysis User Manual Issue 5 1 x 33 34 35 36 37 38 39 40 Al 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 Content of ISGR RISE MOD Data Structure 0 2 000000 ee eae 86 Content of ISGR OFFS MOD Data Structure 87 Content of PICS ENER MOD Data Structure e 87 Content of IBIS GOOD LIM limit table e o o e 87 Instrument Background Model Data Structures e e e o 87 Content of Indexes for Table 37 Data Structures 2 o s 88 List of Data Structures produced at COR level 0 e 89 Content the level COR Data Structures for the photon by photon mode 89 Content the PICS SISH COR IDX Data Structure een 89 Content of IBIS GNRL GTI Data Structures een 89 Content of ISGR DEAD SCP Data Structures e 90 Content of PICS DEAD SCP Data Structures e 90 Content of COMP DEAD SCP Data Structures een 90 List of Data Structures produced at BIN level 91 Content of _ _SHD IDX Data Structures gt occo es s y etete u e eee 91 Content of GNRL REFR CAT Data Structures 2 2 20 20 00 000022 ee eee 91 Content of ISGR SKY IMA IDX Data Structure e 0 00 0 93 Content of ISGR SKY RES Data Structure 2 2 0 0 a 93 Content of IS
15. ISDC IBIS Analysis User Manual Issue 5 1 57 11 Known Limitations Please note that with the time between the releases this list can change For the most update version see http isdc unige ch Soft download osa osa sw osa_sw 5 0 osa_issues txt 11 1 ISGRI 1 The SPSF System Point Spread Function fit may fail does not converge during the sky image generation when there are close sources within 15 20 pixels from the target source 2 In the mosaic build with the option spread 1 the source flux is slightly reduced 10 the fluxes measured in the Science Window 3 Secondary lobes of strong very off axis sources are sometimes not fully corrected cleaned in recon structed images This is possibly due to the approximation in the source modelling 4 The maximum number of sources handled by i spectra erztract is 100 but it is strongly recommended to only fit spectra of the sources that are effectively active visible detectable during the Science Window 5 In general a safe lower limit for the response is 22 5 keV 6 A problem on board IBIS causes event times to be shifted by 2 seconds under some circumstances The software corrects for it The keyword TIMECORR found in ALL or PRP structures of a Sew group indicates whether the correction was done somewhere in this Scw The algorithm is the following 1 detect if there could be a possible 2 sec jump 2 if 1 then look if there was indeed a jump 3 if 2 th
16. P amp V 5 1 0 P amp V 1 sz L5 P amp V 6 1 1 PREV 2 Star re tracker L3 P amp V 4 Vill 1047 1025 DETY Enckplane EN Calibration Sources C DETX cathode JMX2 DETX cathode Calibration Sources Y 9 X pointing Figure 4 d Spacecraft amp Instrument Coordinate Systems Note that the X axis of the spacecraft is defined by the pointing direction ISDC IBIS Analysis User Manual Issue 5 1 6 3 2 The Subsystems 3 2 1 The Mask The IBIS Mask Assembly is rectangular with external dimensions of 1180 x 1142 x 114 mm and consists of three main subsystems the Coded Pattern the Support Panel and the Peripheral Frame with the necessary interface provisions The Coded Pattern is a Square array of size 1064 x 1064 x 16 mm made up of 95x95 individual square cells of size 11 2x 11 2 mm The mask chosen for IBIS is based on a aie replication of MURA Modified Uniformly Redundant Array of order 53 The properties of the MURA patterns are described e g in 11 and 12 Approximately half of the mask cells are opaque to photons in the operational energy range of the IBIS instrument offering a 70 opacity at 1 5 MeV The other 50 of cells are open i e with an off axis transparency of 60 at 20 keV Figure 5 shows the mask pattern Figure 5 The IBIS coded mask pattern The Support Panel includes additional elements to support the code mask pixels providing the necessary stiffne
17. default VETO ATTITUDE ISGRI DATA GAPS SCWI1 GTIPICSIT MergedName string GTIs to be merged for PICsIT default VETO ATTITUDE P_SGLE_DATA_GAPS P_MULE_DATA_GAPS SCW1_GTLSCI SC_Names string Names of spacecraft GTIs to be merged for ISGRI default SCW1_GTISCP SC_Names string Names of spacecraft GTIs to be merged for PICsIT default 12 3 ibis dead This script combine two executables calculating the dead time for ISGRI PICsIT and Compton cases e ibis isgr deadtime e ibis pics deadtime The detector efficiency is divided into the real efficiency and the dead time D which is due to the delay following a photon detection during which another event can not be recorded The observed count rate C is connected with the real count rate C as Co C 1 D The presence of the BGO shielding see Section 3 2 5 calibration source and the Compton coding induces an efficiency loss due to good events which by chance fall in their respective time windows ISDC IBIS Analysis User Manual Issue 5 1 66 For IBIS the term efficiency is reserved for the real physical detection efficiency The effects induced by Veto calibration source and Compton tagging are considered as additional dead times to be added to instrumental dead time Numerically dead time is calculated as the product of the count rate and the time window e g the dead time due to the time of the photon detect
18. spectrum default ISDC IBIS Analysis User Manual Issue 5 1 78 12 9 2 p spectra extract ip spectra extract reads the shadowgram for each each input energy band and the name and coordinates of the source for which a spectrum will be extracted Since PICSIT operates in an energy range with a few sources this executable works for one source only For each output energy band it creates a model PIF for the source The Pixel Illumination Factor PIF is a number between 0 and 1 which expresses the theoretical degree of illumination of each pixel in the detector plane of a coded mask instrument The PIF is calculated on the basis of the position and is normalized to 1 cts pix source The present PIF is purely geometrical by taking into account that there is one single source with ideal PIF than the Equation at pag L228 of Goldwurm et al 2003 can be simplified In this case all the pixel counts depending on the PIF values are due to the selected single source That is deviations from the average counts in the observed shadowgrams are due entirely to the source writes the source count rates in the selected energy bands and the PIF Table 22 ip spectra extract parameters included into the main Script Name Name Type Description in the main script executable PICSIT source name inName string Name of the source for extracting PICsIT spectrum default PICSIT source RA
19. 08g_ibis fits 1 1c 4U1700 377 fits emin 20 lcselect E_MAX 40 The result is written to 4U1700 377 fits It is possible to create more than one merged lightcurve at a time if you specify a list of desired minimum energies with the parameter emin If you have more than one energy range with the same minimal energy then you should use the parameter 1cselect to define the unique energy band otherwise the 1cselect parameter can be omitted 7 3 2 Displaying the Results of the Lightcurve Extraction To see the source lightcurve you should plot the column RATE with error ERROR versus column TIME whereas to see the background lightcurve you should plot column BACKV with error BACKE versus column TIME To display the resulting lightcurve it is convenient to use the curve program from the FTOOLS package lcurve Number of time series for this task 1 Ser 1 filename options or file of filenames options 4U1700 377 fits 2 Name of the window file for default window Newbin Time or negative rebinning 100 Number of Newbins Interval 95 take this number from the line above Maximum Newbin No 95 Name of output file default Do you want to plot your results yes Enter PGPLOT device XW hardcopy 4U1700 377 lc ps PS quit As a result the 4U1700 377_lc ps file was produced and is shown in Figure 21 ISDC IBIS Analysis User Manual Issue 5 1 33 Count sec 100 50 Bin time 100 0 T s
20. 1 t t Ha r t E Ey tout t PF Ps ty Ha ut pe t 1 n t 1 2000 4000 6000 j 8000 10 4 Time s Start Time 12713 23 29 50 496 Stop Time 12714 2 06 30 496 Figure 21 4U1700 377 fits lightcurve in 20 40 keV energy range with 100 sec binning 8 More on ISGRI relevant parameters In the first part of the Cookbook Section 7 the default values of the parameters were used Now it is time to discuss in more details the usage of the main parameters The full list of parameters along with short explanations is given in Table 61 Appendix D 8 1 How to choose the start and end level for the analysis When you launch an analysis you have to decide which levels to perform see Section 5 for a description of the different levels This choice is done with the parameters startLevel and endLevel We recommend to use startLevel COR in any case even if you are using revision 2 data in OSA 5 you have more accurate energy correction than was available at the time of the revision 2 data archiving Therefore it is worth redoing this step Once you have specified startLevel and endLevel all the steps listed in the GENERAL_levelList parameters between these two levels both included will be performed For instance in section 7 1 you used startLevel COR endLevel IMA2 GENERAL_levelList COR GTI DEAD BIN_I BKG_I CAT_I IMA IMA2 BIN_S SPE LCR COMP CLEAN The level
21. 415 16 416 2047 1 To rebin the matrix give the command rbnrmf infile REP_BASE_PROD ic ibis rsp isgr_rmf_grp_0016 fits outfile new rmf fits binfile new_bin txt As a result of this you now have the rebinned response matrix new rmf fits With the help of fv you can see that the rebinned matrix is saved in the third extension of the file For the successful analysis you should make new rebinned matrix read only chmod w new rmf fits To tell the software to use this newly created matrix set in your analysis IBIS_SI_inEnergyValues PATH TO THE FILE new rmf fits 3 otherwise the default 16 channels one will be used corresponding to an empty value of IBIS_SI_inEnergyValues You should also set SCW2_ISPE_idx_isgrResp new rmf fits Warning This parameter is a hidden one in OSA 5 1 Thus you should either provide the value of this parameter during the script launch ibis_science_analysis SCW2_ISPE_idx_isgrResp new rmf fits or press hidden button and set this parameter on the SPE page 9 4 1 Extracting images in more than 10 energy ranges If you want to create images in more than ten energy bands you have to create a rebinned matrix new rmf fits as shown in the text just above Then to create images in the energy ranges defined in the third extension of this file set IBIS_11_ChanNum 1 IBIS_II_inEnergyValues PATH TO THE FILE new rmf fits 3 The first parameter instructs the program to use the energy bounda
22. Analysis User Manual Issue 5 1 19 scw 0051 005100430010 001 swg fits 1 scw 0051 005100440010 001 swg fits 1 scw 0051 005100450010 001 swg fits 1 You should then download them pressing the Request data products for selected rows button In the Public Data Distribution Form provide your e mail address and press the Submit Request button You will be e mailed the required script to get your data and the instructions for the settings of the IC files and the reference catalogue Just follow these instructions e To retrieve the required PICsIT analysis data from the archive proceed in the same manner with the following parameters Object Name Or Coordinates Crab Search Radius default value sew_id 0039 To select only science windows starting with 0039 start_date gt 2003 02 07 06 44 19 and end_date lt 2003 02 07 12 44 05 and save your results in a file called picsit lst which should contain scw 0039 003900020020 001 swg fits 1 scw 0039 003900020030 001 swg fits 1 scw 0039 003900020040 001 swg fits 1 scw 0039 003900020050 001 swg fits 1 scw 0039 003900020060 001 swg fits 1 6 2 Setting the environment Before you run any OSA software you must also set your environment correctly The commands below apply to the csh family of shells i e csh and tcsh and should be adapted for other families of shells In all cases you have to set the REP_BASE_PROD variable
23. Issue 5 1 72 MURA patterns have the remarkable property that their cyclic autocorrelation gives a delta function The decoding array G is inverse to M where G 2M 1 i e G 1 for M 1 and G 1 for M 0 and thus is correlation inverse With the help of array G we can reconstruct the sky S DxG S BxG where S differs from S only by the Bx G term which for a flat array B is a constant level that can be measured and removed To have a sidelobe free response a source must be able to cast a whole basic pattern on the detector fully coded source To make use of all the detector area and to allow more than one source to be fully coded the mask basic pattern is normally taken as the same size and shape of the detector and the total mask made by a cyclic repetition lt 2 x 2 for rectangular mask of the basic pattern For such optimum systems a FCFOV source will always project a cyclically shifted version of the basic pattern and correlating the detector image with the G decoding array will provide a sidelobe free peak with position invariant shape at the source position A source in the PCFOV will instead cast an incomplete pattern and its contribution cannot be a priori subtracted and will produce secondary lobes coding noise On the other hand the modulated radiation from PC sources can be reconstructed by extending the correlation procedure with a proper normalization to the PCFOV URA masks also minimize the statistical e
24. about the event itself See Table 29 for details Data Structures with names finished by PRW and SRW contain some technical information about the structure of the telemetry packet and the Local On Board Time LOBT of the events Table 29 Contest of Photon by Photon Mode Raw Data Column Name Description Event Type DELTA_TIME Delta time to previous event I PS PM RISE_TIME Event rise time describes the shape of the registered I CS CM pulse ISGRLPHA Pulse height in the ISGRI layer I CS CM PICSIT_PHA Pulse height in the PICsIT layer PS PM CS CM ISGRILY Y location in the ISGRI layer I CS CM ISGRI_Z Z location in the ISGRI layer I CS CM PICSIT_Y Y location in the PICsIT layer PS PM CS CM PICSIT_Z Z location in the PICsIT layer PS PM CS CM CAL FLAG Calibration flag 1 when neither of the events are CS CM calibration ones only in this case the event is used in the following analysis TIME TAG Compton delta time to previous event CS CM DUMMY_ COUNTER Dummy counter some technical information used to CS CM reconstruct the On Board Time A 1 2 PICSsIT Standard Mode In this mode the information is accumulated on board and transmitted to the Earth in a kind of histograms Spectral image histograms are written to the Data Structures PICS SISH RAW and PICS SIMH R AW for single and multiple events correspondingly These Data Structures represent a three dimensional ISDC IBIS Analys
25. analysis 55 10 4 PICs Timing Analysis 2 4 4 4 4 05 RE Roo 9 x x x Le s 57 IL Known Limitations 32 45 5444 eee eee Rok ko ee debe besa do Aor y dE n 58 MY ISGRD 222360029 NA 58 112 JPROSUD eri e a RE E apap aei Be we 59 III Data Analysis in Details 60 129 Soene ABalvSiB ugue oed KARR SRE AEA PASS QoS Ra a E CR e GEAERESS 61 12 1 AMSADIECUON ocre E i 61 12 1 0 CREARA e coc Vox ow em A OR AAA s 61 12 1 2 CEE 6 Rob oesequ is a Se ADAC Se EAR Re Henr iU ee dis 61 12 1 9 PeU COMEOHON uou 9m eet ERE ER Oe eae SEE d 64 Wee oc A p PTT 64 1221 EAT os s soo a m RB B REOR REESE eec Ee e UE REOR S d 65 122 2 ghode a ee ien o ex CREE EERE o UE ys 65 12 2 9 IDEO ORE Los y o eoe Oe eee UU NR RO e a LG DR 65 1 DEUDOR AE eRe ee a 65 IND GOTICE sro o e ede uen Dope AUR i ee ee ee SO d 66 We QUISQUE uox ec Roux eR OPUS pO eom SR o DR IUE WU OR Ge e e C e 66 123 1 2ps dagr dead ME ions m RR A EDGES OR m Re RS x 67 123 2 OMSL SCONE uuu uror ne oko baee s XU RR wg a ed e d 67 UBA AED S oe a a ee a X x a A eRe ee ale ae a eee ee S 67 12 11 A a a s Oe REE RU OLA M SO ede EEE ES 68 12 12 evs hodowli ss RR A x a 68 A23 docs Sg NU oa ca eh Re a ee a 69 125 a EEN 70 1260 Jma background dor iaa AAA OR BOX SOR ee a 70 ISDC IBIS Analysis User Manual Issue 5 1 v 12 6 1 H shadow Ub uo sos os sos b voor oc a ea 8 OROROROROR wm 70 1282 OUOU ea g g y m RELA ER Bee Se a ee On 71 JST WDBDSIDESC ca
26. and converts it into a table in ISDC format The user GTI can be defined either in units of OBT IJD or UTC The output is always in OBT The user table can define either bad or good time intervals The output time intervals are always good ones See more details in the Introduction to the INTEGRAL Data Analysis 1 ISDC IBIS Analysis User Manual Issue 5 1 65 Table 8 The gti import parameters included into the main script Name Name Type Description in the main script executable SCW1_GTI gtiUser InGti string DOL of the user GTI table there is no user GTI default SCW1_GTLTimeFormat TimeFormat string Time format in which the user GTI is given possible values IJD UTC OBT default OBT SCW1_GTI Accuracy Accuracy string Used accuracy for OBT to IJD conversion and vice versa possible values any inaccurate accurate default any 12 2 5 gti merge This program merges input GTIs to form a new GTI It is an AND operation a time in the resulting GTI is defined to be good if the time is good in every input GTI The names of the GTIs and the instrument to which the GTI belongs have to be defined as program parameters Table 9 gti merge parameters included into the main script Name Name Type Description in the main script executable SCW1_GTLISGRI MergedName string GTIs to be merged for ISGRI
27. as the last extension e If you are interested in running the analysis in more than 10 energy bands please see Section 9 4 e You can decide if you want to let the software find the best fit position of a source in the vicinity of the one in the catalog default OBS1_SouFit 0 or if you would prefer the catalog position for all sources from the input catalog to be used for the flux determination 0BS1 SouFit 1 If OBS1 SouFit 1 then the position of a new source is always attributed to the pixel center and for catalog sources the catalog position is used for SearchMode 1 3 or the pixel center for SearchMode 2 Note that OBS1 SouFit 1 fixes all the source positions only in the individual Science Window analysis In the mosaic all source positions are always fitted regardless of the value of OBS1_SouFit This fitted values are written to RA FIN and DEC FIN columns of isgri srcl res fits and are later used in spectral and lightcurve extraction steps as a source position To fix the positions of only several sources set for them ISGRI FLAG 2 in the input catalog e For OBS1 SearchMode 1 or 3 where you are forcing a catalog extraction ghosts can be cleaned even from the known sources that happen to have a negative peak This is done using OBS1_NegModels 1 while with OBS1 NegModels empty or equal to 0 the default the deconvolved images will be cleaned from positive source ghosts only 8 3 Spectral and Timing Analysis 8 3
28. at your data is to create an image in order to know how the portion of sky you are interested in looks like whether your source is detected and what other sources you should take into account to do spectral and lightcurve analysis in a proper way ISDC IBIS Analysis User Manual Issue 5 1 23 To start the analysis move to the working directory REP BASE PROD obs isgri gc and call the ibis_science_analysis script cd obs isgri_gc ibis_science_analysis After a few seconds the main page of the IBIS Graphical User Interface GUI appears as shown in Figure 12 ibis_science_analysis 2 Ir m Main Save As Load startLevel cor y Reset endLevel maz y Run Quit Help CAT_refCat risdesarcirev_2 cat nec gnr_refr_cat_0020 1ts 1 SGRI_FLAG 1 browse hidden SWITCH_disablelsgri checked yes SWITCH_disablePICsIT V checked yes SCW1 GTI gtiUserl browse SCW1 GTI TimeFormat iD GENERAL_levelList COR GTI DEAD BIN_I BKG_I CAT_1 IMA IMA42 BIN_S SPE LCR COMP CLEAN FERRED 7 ISGRI IMA ISGRI SPE and LCR PICsIT analysis Figure 12 Main page of the IBIS GUI Keeping all the default values you will make an analysis starting from the energy correction level startLevel COR until the image reconstruction level endLevel IMA2 The default input catalog CAT refCat ISDC_REF_CAT ISGRI_FLAG 1 will be used it contains the sources that were detected by ISGRI in the
29. data gaps x E g 1 gti intport i T gti merge 1 B FR SQ f ibis dead is Fi E ibis isgr deadtinte 3 q Ey ibis_pics_deadtime 1 1 1 3 1 1 ad 1 zi i dica A A MS m um E E TEE ET E i B id general catalog cti og ibis 3 ia e pued E i rebinned E 8 efficiency map E Ecc ccc et P 07 se ip skyimage if staring n0 yi 3 user catalog PSK MAS E gt cW 1 or 1 The ISGRI catalog Eee 418 I sew BIN BKG rebinned wg l step for Spectra background and A i efficiency maps g SC ibis spectral analysis 1 6 ia Tebinned ko 1 5 E background and ii spectra extract sew E i 5 1 efficiency maps l ip spectra extract l n cw i L ew BIN BKG step tor Timing iiri ad efficiency maps i L e a ibis timing analysis Iebinned _ ip st lc extract i y background md jp extract sew Y efficiency maps oe ARNE Fm GRADE ASE EE S Ot SRS GE RS REA B EE ar E ee Le EET REY eg ITO TS aW i es A S INE RIEN NU eR UN IR CE IY E EA em erase Ee e i ibis_clean 8 iM E ibis og ibis ul a ip_skynosaic f staring no 9 2222222222250 oo E Figure 28 B Composition of the main script ibis science analysis For further descriptions of the BIN BKG steps for the DEAD IMA and BIN S levels see Figures 29 30 and 31 respectively ISDC IBIS Analysis User Manual Issue 5 1 62 Binning backgroud step for IMA ibi
30. inRA real RA of the source for extracting PICsIT spectrum default PICSIT source DEC inDEC real DEC of the source for extracting PICsIT spectrum default 12 10 Timing Analysis 12 10 1 2 lc extract ii lc extract performs similar tasks to di spectra erztract dealing with time bins instead of spectra ones Table 23 Parameters for the lc extract Name Name Type Description in the main script executable ISGRI mask mask string DOL of the MASK pattern fits file default SCW2 cat for extract inCat string DOL of the subset of the source catalogue default SCW2 ISPE DataMode DataMode integer Data Simulation mode DataMode 0 gt OG shadowgrams are treated 1 gt shadowgrams are simulated ISDC IBIS Analysis User Manual Issue 5 1 79 SCW2_ISPE_MethodInt MethodInt integer Method to be applied for the pixel value interpolation This parameter should have the same value as in the ii shadow build In the source model procedure MethodInt 0 gt dead zone pixels will be filled with 0 1 gt dead zone pixels will be filled with mean de tector value gt no dead zones SCW2_ISPE_MethodFit MethodFit integer Method to be applied for background and source in tensity fitting default 6 SCW2_ISPE_isgrUnifDol isgrUnifDol string DOL of the ISGRI detector uniformity default SCW2 BKG LisgrBkgDol isgrBkgDol string DOL of the IS
31. main script o 69 ip si shadow build parameters included into the main script 69 ii map rebin parameters included into the main script 70 ii_shadow_ubc parameters included into the main script 71 ip_shadow_ubc parameters included into the main script css 71 cat extract parameters included into the main script o 0000002 eee 72 ii skyimage parameters included into the main script o e 0 000 75 sumhist parameters included into the main script o e eee ee 77 ip_skyimage parameters included into the main script sss 77 ii spectra extract parameters included into the main script 2 78 ip spectra extract parameters included into the main script 0 79 Parameters for th dc ERC i124 ERE ER EARS S 79 Parameters for the 2p st le exbracl usos sees o sos eee ee Re 80 ip skymosaic parameters included into the main script 80 MOSBIC SDEC parameters ooo o o9 Ee Rhee EE A 9 odo 81 OE USA C vici c PDC TI 82 List of IBIS RAW Data Structures gt o saca oo mmm REA RES 84 Contest of Photon by Photon Mode Raw Data es 84 Content of PICS SPTI RAW Data Structure 22s 85 Content of ISGR SWIT STA Data Structure 02 2000 eee ee eee 86 Content of PICS FALT STA Data Structure lt a aaa ow x e544 8 oe we RARE EG 86
32. number is indicated at the top The black pixel are the killed ones The Y Z coordinates are the IBIS ones both ranging from 0 to 63 X axis is directed toward the source located above the page The Z axis is pointing positively to the sun or induced in the spacecraft The sides up to the ISGRI bottom level and rear of the stack of detector planes are surrounded by an active Bismuth Germanate BGO veto shield Like the detector array the Veto shield is modular in construction There are 8 lateral shields i e 2 modules per side and 8 bottom modules The high density and mean Z of BGO ensures that a thickness of 20 mm is sufficient to reduce the detector background due to leakage through the shielding of cosmic diffuse gamma ray background and gamma rays produced in the spacecraft to less than the sum of all other background components ISDC IBIS Analysis User Manual Issue 5 1 10 4 How the Instrument works 4 1 Event Types The photon entering the telescope can be detected due to its interaction with the absorbing material of the detector Three major types of interactions play a dominant role photoelectric absorption Compton scattering and pair production In the photoelectric absorption process a photon undergoes an interaction with an absorber atom in which the photon completely disappears In its place an energetic photoelectron is ejected by the atom carrying away most of the original photon energy The Compton scattering
33. of launching the analysis 6 3 1 Graphical User Interface GUI When you launch the analysis the Graphical User Interface GUI is launched providing an opportunity to set the values of all desired parameters see Figure 12 On the right side of the panel you see the following buttons e Save as With the Save As button a file is created This file stores all parameters as they are currently defined in the GUI as a command line script This file is an executable one and calling it from the command line will launch the instrument analysis program with the parameters as they were defined in the GUI e Load With the Load button a previously saved file see Save As can be read and the GUI will update all parameters with the values as they are defined in the loaded file e Reset With the Reset button the parameters in the GUI will be reset to the default values as they are defined in the parameter file of the instrument analysis program and stored in the ISDC_ENV pfiles directory e Run With Run button the analysis is launched e Quit With Quit button you quit the program without analysis launch e Help With Help button the help file of the main script is opened in a separate window e hidden With the hidden button you have an access to the hidden parameters with values defined by the instrumental teams Change them with care 6 3 2 Launching scripts without GUI Alternatively parameters can be specified on
34. takes place between the incident gamma ray photon and an electron in the absorbing material The incoming photon is deflected and it transfers a portion of its energy to the electron The energy transferred to the electron can vary from zero to a large fraction of the initial gamma ray energy In the pair production process the gamma ray photon disappears and is replaced by an electron positron pair The positron will annihilate in the absorbing medium and two annihilation photons are normally produced as secondary products of the interaction Depending on the size of the detector and on the energy of the incoming photon a photon scattered in a Compton interaction can escape the detector or undergo a second interaction The pairs of 511 keV photons produced by the annihilation of the positrons resulting from pair creation can also produce other interactions or escape the detector Both ISGRI and PICsIT record the coordinates of each event registered in the corresponding layer to build up an image The anticoincidence VETO is used to reject background events The coded mask produces a shadowgram Photons from the source and the background are distributed across the entire field of view but cross correlation techniques allow the full image to be reconstituted for the fully coded field of view 9 x9 at each pointing For the partially coded field of view out to 29 x 29 special cleaning techniques must be applied to the data to properly recons
35. the selected sources See Section 12 7 for more details IMA ISGRI and PICsIT staring Image Reconstruction In the case of ISGRI shadowgrams are deconvolved source search is performed in the single images as well as in the mosaic combination of different images and a list of detected sources is created If INTEGRAL was stable during the whole period of interest then at your request all PICsIT shad owgrams are combined into one and then are deconvolved into a single image See Section 12 8 for more details e The third script ibis scw2 analysis again works Science Window by Science Window and performs the following tasks IMA2 PICsIT Image Reconstruction PICSIT shadowgram deconvolution is done at this step creating a separate image for each science window See Section 12 8 3 for more details Nothing is done at this step for ISGRI BIN S Event Binning for Spectra Creates rebinned maps for background and absorption of support mask see Section 3 2 1 corrections Sorts data into energy bins For each energy range the shadowgram and a corresponding efficiency shadowgram is created See Sections 12 4 12 6 for more details SPE ISGRI spectra extraction For each source of interest one PIF is produced ISGRI spectral extraction is done for all catalog 2PIF is a number between 0 and 1 which expresses the theoretical degree of illumination of each detector pixel for a given source in the sky ISDC IBI
36. the sources by class default OBS1_CAT date date string IJD for the public data possible values lt 0 all public O all private gt 0 according to DAY ID date default 1 12 8 Image analysis The IBIS telescope is a device based on a coded aperture imaging system The mask chosen for IBIS is based on a cyclic replication of MURA Modified Uniformly Redundant Array of order 53 expanded to 95 pixels The properties of the MURA patterns are described in the papers 11 12 For IBIS the mask is about 1 8 times larger than the detector The most important advantage of such configuration is that for a large fraction of the sky a source projects a complete pattern on the detector the Fully Coded Field Of View FCFOV The part of the sky from which only a fraction of the source radiation directed towards the detector plane is modulated is called Partially Coded Field of View PCFOV The complete field of view of the telescope FOV is therefore composed by the central FCFOV of constant sensitivity and optimum image properties surrounded by the PCFOV of decreasing sensitivity A source outside the FOV simply contributes to the background level Representing the mask with an array M of 1 open elements and 0 opaque ones the detector array D will be given by the convolution of the sky image S by M plus an unmodulated background array term B D SxM B ISDC IBIS Analysis User Manual
37. time interval ISDC IBIS Analysis User Manual Issue 5 1 96 Table 59 Content of the GNRL EVTS LST Data Structure Column Name Description DETY DETZ ENERGY EVNT_TYPE TIME TIMEDEL DEADC BARYTIME_N PIF_N AREASCAL_N Y location in the detector layer offset from center Z location in the detector layer offset from center Energy deposited by the event Type and origin of event bit coded Time of event in INTEGRAL Julian Date units Uncertainty of time stamp Dead time correction factor Barycenter time for source number N Pixel Illumination Factor for source number N Nominal effective area for source number N Table 60 Content of the GNRL EVTS GTI Data Structure GNRL EVTS GTI Table 60 contains good time intervals for selecting events Column Name Description START IJD of start of the GTI STOP IJD of end of the GTI OBT START On board time of start of the GTI OBT_END On board time of end of the GTI UTC_START UTC of start of the GTI UTC_END UTC of end of the GTI ISDC IBIS Analysis User Manual Issue 5 1 97 D List of bis science analysis parameters Table 61 ibis science analysis parameters description Query pa rameters are marked with bold font Name Type Description General parameters ogDOL string DOL of the Observational Group to be analyzed default og ibis fits 1 startLevel string Analysis level at which the analysis beg
38. to the location where you perform your analysis e g the directory ibis data rep Thus type setenv REP BASE PROD PWD Then if not already set by default by your system administrator you should set some environment variables setenv ISDC ENV directory of 08A sw installation setenv ISDC REF CAT REP BASE PROD cat hec gnrl refr cat 0023 fits 1 source ISDC ENV bin isdc init env csh The latter command executes the OSA set up script isdc_init_env csh which initialises further environ ment variables relative to ISDC_ENV Ignore all warnings mentioning ROOTSYS Besides these mandatory settings the optional environment variable COMMONLOGFILE can also be useful By default the software logs messages to the screen STDOUT To have these messages in a file i e common log txt and make the output chattier use the command setenv COMMONLOGFILE common_log txt 4If the setenv command fails with a message like setenv command not found or setenv not found then you are probably using the sh family In that case please replace the command setenv my_variable my_value by the following command sequence my_variable my_value export my_variable In the same manner replace the command source a given script csh by the following command a given script sh the is not a typo 5For example the exit status of the program will now appear ISDC IBIS Analysis User Manual Issue 5 1 20 6 3 Two ways
39. 00 44 oe ee RRA SY Dew e ae X 87 OG Seine Data Products nuera Rubeo somos Phe ee speed dee eae dd 89 LL OGDELCOPIBOHOR aos e 9 ok Vb xg PEG Yee B E peed UN Pes 89 ISDC IBIS Analysis User Manual Issue 5 1 vi C2 E A E E E E ES E E Cas WIS OW Goha ee ee ee Ee y A C 4 TONEN aca OSL AA C 4 1 Wi shadow bwild C 5 BRI IROL Eases vor oR a X Xen C 6 ibas DACKOTOUNG COP Sees is C 7 Image Analysis rad QLSEUIMOS css os oy osx xen E POGRADE vo cdi mrs C 8 Spectral Analysis C 8 1 ii_spectra_ertract C 9 Timing Analysis C 9 1 ipsi le esaet vois cca C 9 2 MNCLOTIFOCE cr we 650 3 Timing Analysis without the deconvolution D List of ibis science analysis parameters ISDC IBIS Analysis User Manual Issue 5 1 vii List of Figures 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 ISDC IBIS GHOchbVe BREA 200 a A RR A G Ga 4 Cutaway drawing of the IBIS detector assembly together with the lower part of the collimator 4 05 E 5 IBIS detector assembly in nUMbers e 5 Spacecraft amp Instrument Coordinate Systems o 6 The IBIS coded Mask pattem 2 9o Roe RR Rob X XU ee er ee EEUU 7 The cross section of the support panel e eee ee ee 8 ISGRI and PICsIT division in modules and submodules 9 The schematic view of PICsIT layer o o
40. 001 swg fits 1 scw 0039 003900020050 001 swg fits 1 scw 0039 003900020060 001 swg fits 1 The created files contain the list of Scws you want to analyze technically we call them DOLs Data Object Locators i e a specified extension in a given FITS file These file names isgri_gc lst and picsit Ist will be used later as an argument for the og_create program see Sections 7 10 6 1 1 Downloading data from the archive e To retrieve the required ISGRI analysis data from the archive go to the following URL http isdc unige ch index cgi Data browse You will reach the W3Browse web page which will allow you to build a list of Science Windows SCWs that you will analyse with OSA Type the name of the object 4U 1700 377 in the Object Name Or Coordinates field Do not forget to change Search Radius if you are interested in science windows where your source is in the partially coded field of view Set it to e g 10 degrees Click on More Options button at the top or at the bottom of the web page Deselect the All checkbox at the top of the Catalog table and select the SCW Science Window Data one Press the Specify Additional Parameters button at the bottom of the web page Introduce values in the fields of interest For instance Sort output by scw_id for that check the Sort column Put pointing in the field scw type to specify that only pointings should b
41. 02 4U1700 sum pha fits SYS ERR add yes xspec cpd xw data 4U1700_sum_pha fits setpl energy ign 22 5 ign 150 plot ldata model cutoffpl 1A 33 3 fit 100 plot ldata del ISDC IBIS Analysis User Manual Issue 5 1 31 The resulted 4U 1700 377 total spectrum is shown in Figure 20 Please note that in OSA 5 0 reconstructed ISGRI spectra are not accurate below 17 keV ISGRI systematic is believed to be equal to 1 In the very same manner you can sum up the spectra for all the sources of the input catalog specified in the SCW2_cat_for_extract parameter data and folded madel 4U1700_sum_pha fite T T T r T T 0 5 0 2 normalized counts sec keV 0 1 0 05 channel energy keV chemyak 17 Ho 2005 15 01 Figure 20 Total 4U 1700 377 spectrum Usage of spe pick for spectra created in different observation groups is explained in Section 9 7 3 Lightcurve Extraction After you have done the spectral extraction you may want to produce a lightcurve for the same sources Stay in the working directory REP BASE PROD obs isgri gc and call the ibis science analysis script again On the main GUI window see Figure 12 change both Start Level and End Level to LCR and press the ISGRI SPE and LCR button The GUI shown in Figure 18 will appear Note that to extract the lightcurve for a source you need the Pixel Illuminated Fraction PIF map Such a map is c
42. 1 Spectral Energy Binning With the help of the IBIS_SI_inEnergyValues parameter you can specify the desired binning of the response matrix See Section 9 4 for the detailed discussion on how to rebin the original response matrix ISDC IBIS Analysis User Manual Issue 5 1 37 In case you using a response matrix rebinned on your own you should set SCW2_ISPE_idx_isgrResp your_rebinned_matrix fits Warning This parameter is a hidden one in OSA 5 1 Thus you should either provide the value of this parameter during the script launch ibis_science_analysis SCW2_ISPE_idx_isgrResp your_rebinned_matrix fits or press hidden button and set this parameter on the SPE page 8 3 2 Background Subtraction In spectral and timing analysis you can choose with the help of the parameter SCW2 BKG I isgrBkgDol whether you want to subtract the instrumental background or not similarly to the imaging case We recommend you to use the option that gives the best results at the imaging level smoother image no clear patterns etc See 8 2 3 for more information 8 3 3 Input catalog The single Science Window and mosaic imaging results are merged in the file isgri srcl res fits By default a spectrum and a lightcurve will be created for all sources listed in this file Spectral lightcurve extraction is time consuming and we recommend you to create an input catalog for spectral and timing extraction as discussed in Section 7 2 The spectrum and lightcurv
43. 12 1 mosaic spec mosaic spec is a tool that extracts a count spectrum at a given sky position from a set of mosaic sky images Intensity could be measured in a specific or in the most significant pixel or derived from a gaussian fit with free or frozen position and width Note that if the significance of the point is less than five then mosaic_spec will assign a non zero value to its quality flag Table 26 mosaic_spec parameters Name hline DOL_inp DOL out EXTNAME DOL idx DOL spec ximg yimg ra dec posmode widthmode Type string string string string string real real real real integer integer Description DOL of the group containing the input images default DOL of the group containing the output images 6699 default EXTNAME of the input images default ISGR MOSA IMA DOL of the index of input images default DOL of the index of output images default h 0 0 10000 Enter source x in pixels possible values 0 10000 default O Enter source y in pixels possible values O 10000 default 0 Enter source RA possible values 180 360 default 0 Enter source DEC possible values 90 90 default 0 Position fitting mode posible values 1 freeze position as input 0 position is always left free 1 freeze position as found in first energy band default 1 Gaussian width fitting mode posible valu
44. 15 keV and PICsIT starts from 200 keV and sensitivity and are optimised for different targets This is why we have decided to guide you through the analysis of the crowded Galactic Centre around 4U 1700 377 for ISGRI and of the bright Crab for PICsIT Here we assume that you have already successfully installed ISDC Off line Scientific Analysis OSA Software version 5 0 the directory in which OSA is installed is later on referred to as the ISDC_ENV directory If not then look at the Installation Guide for the INTEGRAL Data Analysis System 5 for detailed help 6 1 Setting up the analysis data In order to set up a proper environment you first have to create an analysis directory e g ibis_data_rep and cd into it mkdir ibis_data_rep cd ibis_data_rep This working directory ibis data rep will be referred to as the REP BASE PROD directory in the following All the data required in your analysis should then be available from this top directory and they should be organized as follows e scw data produced by the instruments e g event tables cut and stored by ScWs e aux auxiliary data provided by the ground segment e g time correlations e cat ISDC reference catalogue OSA CAT package e ic Instrument Characteristics IC such as calibration data and instrument responses OSA IC package e idx set of indices used by the software to select approriate IC data OSA IC package The cat ic a
45. 1_ToSearch OBS1_CleanMode OBS1_ExtenType OBS1_NegModels OBS1_FastOpen integer real string integer integer integer integer integer integer Data Simulation mode possible values 0 shadowgrams are treated 1 shadowgrams are simulated default 0 Spectral slope to be used default 2 DOL of the ISGRI arf for rebinning default Source search mode possible values for the Science Window analysis 1 search for all catalog sources 2 search for K sources where K ToSearch 3 search for all catalog sources plus for K significant excesses where K ToSearch For all the above when the mosaic is created the software looks for K ToSearch sources default 2 Number of sources to be looked for default 15 Ghost cleaning possible values 1 source model lobes are subtracted from the decon volved image 1 no subtraction default 1 Save exposure residual maps possible values absent 0 3 O or absent no action 1 true exposure maps are saved in 4 n extension of isgri sky ima fits instead of residual images 2 true exposure maps are saved in the 5 n extension of isgri sky ima fits after the residual images 3 one true exposure map is created for the last energy band and saved in the last extension of is gri sky ima fits default 0 0 or absent for no negative models 1 negative models default 0 if 1 then no CommonPrepar
46. DOL string DOL of the energy correction table PICsIT default 12 2 ibis gti This script builds Good Time Interval GTI information from housekeeping data information about the satellite stability and data gaps It calls the following executables to obtain the GTIs gti create gti attitude gti data gaps gti import e gli merge For the definition of GTI see Introduction to the INTEGRAL Data Analysis 1 ISDC IBIS Analysis User Manual Issue 5 1 64 12 2 1 gti create This program generates all GTIs for one instrument that depend on HK and other parameters and are defined by a limit in a limit table see details in Section B 3 In ISGRI case it creates VETO GTIs during which VETO was switched on and ISGRI_MCE7X where X varies from 0 to 7 GTIs during which the Xth module was switched on VETO GTIs are taken into account by gti merge executable see Section 12 2 5 and ISGRI MCE7X GTIs are taken into account later during BINI BIN S and BIN T levels Table 6 gti_create parameters included into the main script Name Name Type Description in the main script executable SCWI GTILimitTable LimitTable string The DOL of the GTI limit table default 12 2 2 gti attitude A GTI is defined for each period of time where the pointing stability is better than the accepted tolerance parameter AttStability This GTI is named ATTITUDE For slews this GT
47. GAIN for average gain value in units keV channel and AVOFFSET for average offset value in keV Table 35 Content of PICS ENER MOD Data Structure Column Name Description PICSIT_Y Y location in the PICsIT layer PICSIT_Z Z location in the PICsIT layer GAIN Gain OFFSET Offset B 3 Limit Tables Instrument GTIs depending on HK and other parameters are defined by a limit in a limit table IBIS GOOD LIM see details in Table 36 Table 36 Content of IBIS GOOD LIM limit table Column Name Description PAR_NAME Parameter name OBT_START Start of validity of the limit values OBT_END End of validity of the limit values MIN_VAL Minimum value allowed MAX_VAL Maximum value allowed GTINAME Name of the group to which the parameter belongs SUB_ASSEMBLY Identifier of the instrument sub assembly CHECK_MODE Modes in which the parameters must be checked B 4 Instrument Background Table 37 lists Data Structures with the instrument background models Table 37 Instrument Background Model Data Structures Data Structure Description ISGR BACK BKG ISGRI instrument background array ISGR UNIF BKG ISGRI instrument background uniformity array PICS SBAC BKG PICsIT instrument background array for single events PICS SUNI BKG PICsIT instrument background uniformity array for single events PICS MBAC BKG PICsIT instrument background array for multiple events PICS MUNI BKG PICsIT instrument background uniformity a
48. GR SKY RES IDX Data Structure leen 93 New information added to the ISGR SRCL RES Data Structure o o 94 Content of the ISGR OBS RES Data Structure e 94 Content of the ISGR EVTS SPE Data Structure en 95 Content of the ISGR EVTS SPE IDX Data Structure o e 95 Content of the PICS EVTS LCR IDX Data Structure o a 96 Content of the PICS EVTS LCR Data Structure eee 96 Content of the ISGR SRC LCR IDX Data Structure o leen 96 Content of the GNRL EVTS LST Data Structure 97 Content of the GNRL EVTS GTI Data Structure eee 97 ibis science analysis parameters description e e e 98 ISDC IBIS Analysis User Manual Issue 5 1 xi Acronyms and Abbreviations AD ADD A D AFEE ASIC BGO CdTe CsI DBB DFEE DOL DPE DS FCFOV FIFO FOV FWHM GPS GTI GUI ISDC IBIS Analysis User Manual Issue 5 1 Architectural Design Architectural Design Document Analog Digital Analog Front End Electronics Application Specific Integrated Circuits Bismuth Germanate Cadmium Telluride Caesium lodide Detector Bias Box Digital Front End Electronics Data Object Locator Data Processing Electronics Data Structure Fully Coded Field of View First In First Out Field of View Full Width at Half Maximum Galactic Plane Scan Good Time Interval Graphical User Interface HEPI HV IC I
49. GRI background model default SCW2_ISPE tungAtt tungAtt string DOL of the Tungsten attenuation length fits file default SCW2_ISPE_aluAtt aluAtt string DOL of the Aluminium attenuation length fits file default SCW2_ISPE leadAtt leadAtt string DOL of the Lead attenuation length fits file default rebinned corrDol lc corrDo string DOL of the rebinned ISGRI off axis corrections for lc default 12 10 2 ip st lc extract This program builds PICsIT detector light curves and related errors starting from spectral timing data of PICsIT Table 24 Parameters for the ip_st_lc_extract Name Type Description inGRP string DOL of the input group inCorSPT string DOL of the input Corrected SPT histogram inDead string DOL of the dead times outGRP string DOL of the output group outLCR string DOL of the light curves 12 11 Summing up the results 12 11 1 ip skymosaic ip skymosaic creates a mosaic image of all the science windows within an Observation Group and performs a source location Table 25 ip_skymosaic parameters included into the main script Name Name Type Description In the main script OBS2_detThr detThr real Detection Threshold in Sigmas default 3 OBS2_projSel projSel string Selection of projection default TAN ISDC IBIS Analysis User Manual Issue 5 1 80 12 12 Tools not included in the pipeline 12
50. I is always set to be good independently of any input data If the necessary data are not available the GTI is set to be not good for the whole Science Window Table 7 gti_attitude parameters included into the main script Name Name Type Description in the main script executable SCWI1 GTLattTolerance AttStability real Defines the accepted attitude stability tolerance in units of arc minutes A GTI is created if the stability is better than this tolerance default 0 5 12 2 3 gti data gaps This program generates GTIs for ISGRI and PICsIT The GTIs depend on the presence of the science data A time is defined as bad if a science packet of the instrument is missing The expected science packets depend on the actual mode of the instrument This is taken into account while the GTI is being created The program does not distinguish between a pointing a slew and an engineering window The time is also set to be bad if there are scientific data that do not agree with the reported mode of the instrument Time is also defined bad if the telemetry indicates that there was an interruption of the on board processing due to a telemetry saturation In normal operation this case is rather seldom The final GTI is written into the IBIS index group and has the name ISGRI DATA GAPS and PIC SIT_DATA_GAPS for ISGRI and PICsIT correspondingly 12 2 4 gti import The gti import reads the user GTI table
51. IS Analysis User Manual Issue 5 1 1 Part I Instrument Definition ISDC IBIS Analysis User Manual Issue 5 1 2 Scientific Performances Summary IBIS is a gamma ray telescope observing celestial objects of all classes ranging from the most compact galactic systems to extragalactic objects with powerful diagnostic capabilities of fine imaging source identification and spectral sensitivity in both continuum and lines It is able to localize weak sources at low energy to better than a few arcminutes accuracy covering the entire energy range from a few tens of keV to several MeV Table 1 gives an overview of the scientific capabilities of IBIS The effective area curves are given on the Figure 1 Table 1 Scientific Parameters of IBIS Operating energy range 15 keV 10 MeV Energy resolution FWHM 7 100 keV 9 1 MeV Effective Area ISGRI 960 cm at 50 keV PICsIT 870 cm at 300 keV single events PICsIT 275 cm at 1 MeV multiple events Field of view 9 x 9 fully coded 19 x 19 partially coded 50 Angular resolution FWHM 12 Point source location accuracy 30 100 keV 90 error radius lt 5 1 MeV Continuum sensitivity 3 8 x 1077 100 keV photons cm s keV 1 2x107 Q 1 MeV 30 detection AE E 2 10 s integration Narrow line sensitivity 1 3 x 1075 100 keV photons cm s 4 x 1075 1 MeV 30 10 s integration Absolute timing accuracy 3 c ISGRI 61 u
52. JD ISDC ISOC MCE MDU OBT OG PCFOV PEB PIF PMT PLM RMF ScW SWG TBW TM Hardware Event Processor High Voltage Instrument Characteristics Integral Julian Day Integral Science Data Center Integral Science Operations Centre Module Control Electronics Modular Detection Units On Board Time Observation Group Partially Coded Field of View PICsIT Electronic Box Pixel Illuminated Factor Photomultiplier Tube Payload Module Redistribution Matrix Files Science Window Science Window Group To be written Telemetry xii Glossary of Terms e ISDC system the complete ground software system devoted to the processing of the INTEGRAL data and running at the ISDC It includes contributions from the ISDC and from the INTEGRAL instrument teams e Science Window ScW For the operations ISDC defines atomic bits of INTEGRAL operations as either a pointing or a slew and calls them ScWs A set of data produced during a ScW is a basic piece of INTEGRAL data in the ISDC system e Observation Any group of ScW used in the data analysis The observation defined from ISOC in relation with the proposal is only one example of possible SDC observations Other combinations of Science Windows i e of observations are used for example for the Quick Look Analysis or for Off Line Scientific Analysis e Pointing Period during which the spacecraft axis pointing direction remains stable Because of the INTEGRAL dithering strategy the nomin
53. Num integer Number of output energy bands for ISGRI possible values 1 10 value 1 is for more than 10 energy bands in this case IBIS II inEnergyValues should be set default 4 ISDC IBIS Analysis User Manual Issue 5 1 99 IBIS II E band min string List of lower limits of output energy bands keV for ISGRI default 20 40 60 100 IBIS II E band max string List of upper limits of output energy bands keV for ISGRI default 40 60 100 200 IBIS II inEnergy Values string DOL of the energy values when required default default 0 IBIS IPS_corrPDH integer Packets threshold for partially downloaded his tograms default 0 IBIS IPS_ChanNum integer Number of Energy bands for PICsIT in standard mode possible values 0 300 You should set it to 0 to build automatically the only binning for which background maps are present It corresponds to the following energy ranges keV 203 252 252 329 329 455 455 655 655 1057 1057 1841 1841 3570 3570 6510 default 0 IBIS IPS E band min s string List of lower energy boundary for PICsIT in standard mode for SINGLE Do not touch this parameter default 170 600 1000 IBIS IPS E band max s string List of higher energy boundary for PICsIT in standard mode for SINGLE Do not touch this parameter default 600 1000 10000 IBIS IPS_E_band_min_m string List of lower energy boundary for PICsIT
54. OBT_FAULT OBT when the pixel is switched off FALT_ FLAG FLAG reflecting the changes of the pixel status Possible values are ON OFF and OFF ON B 2 Calibration Corrections B 2 1 ISGRI To perform a rise time correction for each raw ISGRI event the Rise Time correction table is used ISGR RISE MOD Data Structure see details in Table 33 This table is composed of NUM_ENER lines giving for each incident energy the correction factor corr for a given value of the rise time Table 33 Content of ISGR RISE MOD Data Structure Column Name Description ENERGY Energy at which the gain offset relationship is measured CHANNEL Channel at which the gain offset relationship is measured CORR Rise time correction for a given rise time value 0 127 The rise time itself and the gain offset are kept at the ISGR OFFS MOD Data Structure ISDC IBIS Analysis User Manual Issue 5 1 86 Table 34 Content of ISGR OFFS MOD Data Structure Column Name Description AGAIN Amplitude Gain AOFFSET Amplitude Offset RTGAIN Risetime Gain RTOFFSET Risetime Offset PIXTYPE Pixel type B 2 2 PICsIT Data Structure PICS ENER MOD is created by the PICsIT Automatic Calibration Analysis and contains parameters for gain and offset correction of PICsIT raw events Content of this Data Structure is given in the Table 35 The values given in the Table 35 are normalized to the average values given by the keywords AV
55. S Analysis User Manual Issue 5 1 16 sources with the use of these PIFs See Section 12 9 for more details LCR PICsIT Detector Light Curve Creation and ISGRI source lightcurve extraction At this step PICsIT Detector light curves are built from the spectral timing data For all sources from the input ISGRI catalog light curves are extracted See Section 12 10 for more details CLEAN Last step At this step PICsIT mosaic is created See Section 12 11 for more details As of October 18 2004 all public INTEGRAL data are available in two formats revision 1 and revision 2 In revision 2 data the correction of all JD time stamps for the offsets between the OBT of each instrument is done and as all data are available in revision 2 format data in revision 1 format become obsolete For revision 2 data the data correction step COR as well as the instrumental GTI and deadtime handling DEAD steps have already been performed using version 4 2 of OSA at the science window level However the data correction implemented in OSA 5 0 is much better and it is highly recommended to rerun these steps starting from the COR level ISDC IBIS Analysis User Manual Issue 5 1 17 6 Getting started This chapter describes how to set up the the environment and the analysis data and how to analyse data from the two instruments that are part of IBIS ISGRI and PICsIT These two instruments are quite different in energy range ISGRI starts from
56. TS Comments SPLFLUX_1 SPI flux in the soft SPI energy band SPLFLUX 2 SPI flux in the hard SPI energy band ISGR FLUX 1 ISGRI flux in the soft ISGRI energy band ISGR FLUX2 ISGRI flux in the hard ISGRI energy band PICS FLUX 1 PICsIT flux in the soft PICsIT energy band PICS FLUX 2 PICsIT flux in the hard PICsIT energy band JEMX FLUX JEMX flux in the soft JEMX energy band JEMX FLUX 2 JEMX flux in the hard JEMX energy band E_MIN Lower energy boundaries E_MAX Upper energy boundaries FLUX Flux values FLUX_ERR Flux errors SEL FLAG Source selection flag FLAG Generic flag C 6 ibis background cor This script combines executables performing the background correction in accordance with the chosen method As the output for each energy range for ISGRI shadowgrams of larger dimensions corrected expanded shad owgram and corresponding variance and efficiency expanded shadowgrams are written to ISGR CEXP SHD The energy range is given in the keywords E MIN E MAX CHAN MIN CHAN MAX and a shadowgram type is given by SHD TYPE keyword For PICsIT Data Structures PICS CEXP SHD and PICS VEXP SHD are filled for the corrected ex panded detector shadowgram and the corrected expanded variance detector shadowgram The energy range is again given in the keywords C 7 Image Analysis C 7 1 4 skyimage Vi skyimage deconvolves shadowgrams in the given energy bands The index of deconvolved and cleaned images is written to ISGR SK
57. The file REP BASE PROD ic ibis rsp isgr rmf grp 0016 fits contains the latest full response matrix with 2048 channels With the help of the FTOOLS 5 3 program rbnrmf you can rebin this matrix accord ing to your needs The default rebinned matrix is REP BASE PROD ic ibis rsp isgr rmf grp 0017 fits 15please note that it will not work with the earlier versions of the program ISDC IBIS Analysis User Manual Issue 5 1 42 and has 16 energy bins in its third extension The optimum way to rebin the matrix depends on the source and on what you are interested to study so there is not a general best way to rebin it Nevertheless it is reasonable not to spend time on a fine energy binning where the source is too weak and background contaminated as well as it is better to avoid too narrow energy bins for weak sources extracting a spectrum in wider energy bins from the very beginning is better than extracting it in too fine bins being background contaminated and then rebinning the spectrum afterwards To use rbnrmf you should create an ASCII file with three columns representing minimal and maximal channels and the compression factor In the example below we create the file new_bin txt in order to apply a compression factor of 16 to channels 16 415 20 6592 212 1392 keV and ignore all the others This will lead to maximal_channel minimal_channel 1 compression factor number of final bins i e in this example to 25 bins 0 15 f 16
58. Y IMA IDX Data Structure For each output energy band defined four images are created and attached to this index The content of this Data Structure is given in the Table 49 ISDC IBIS Analysis User Manual Issue 5 1 92 Table 49 Content of ISGR SKY IMA IDX Data Structure Column Name Description IMATYPE Type of image Possible values are IMAGE deconvolved and cleaned sky image VARIANCE variance image SIGNIFICANCE significance map RESIDUAL difference between raw deconvolved only and cleaned image EXPOSURE true exposure map can be cre ated CHANMIN Lowest channel of the energy range CHANMAX Highest channel of the energy range E_MIN Lower bound of the energy range E_MEAN Mean energy of the energy range E_MAX Upper bound of the energy range TFIRST Time of the first data element TLAST Time of the last data element TELAPSE Total elapsed time of the data EXPOSURE Effective exposure time CRVAL1 LONG at the reference value CRVAL2 LAT at the reference value For each deconvolved image the list of found sources is created Data Structure ISGR SKY RES and attached to the ISGR SKY RES IDX Data Structure See content of these Data Structures in Tables 51 50 Table 50 Content of ISGR SKY RES Data Structure Column Name Description NEW SOURCE New source flag 0 if old 1 if new SOURCE ID ISDC unique source identifier RA_OBJ Source right ascensio
59. _method_int string Method to be applied for the pixel value interpolation default 1 SCW2 BKG P method integer Method applied in filling gaps possible values 0 2 default 1 SCW2 BKG picsSUnifDOL string DOL of the PICsIT Detector Uniformity model sin gle default SCW2 BKG picsSBkgDOL string DOL of the PICsIT Detector Background model sin gle default SCW2 BKG picsMUnifDOL string DOL of the PICsIT Detector Uniformity model mul tiple default SCW2 BKG picsMBkgDOL string DOL of the PICsIT Detector Background model mul tiple default Parameters for lightcurve extraction ILCR select string Event selection condition default ILCR delta t real Time bin in seconds possible values 0 1 10000 default 100 ILCR num e integer Number of energy channels possible values 1 10 default 4 ILCR e min string List of low energy boundaries default 20 40 60 100 ILCR e max string List of high energy boundaries default 40 60 100 200 ISDC IBIS Analysis User Manual Issue 5 1 109 OBS2_detThr real Detection Threshold in sigmas default 3 0 OBS2 projSel string Selection of projection default TAN default TAN OBS2 imgSel string Selection criteria of images default EVT_TYPE SINGLE amp amp E MIN 252 amp amp E MAX 336 References ISDC OSA INTRO Introduction to the INTEGRAL Data Ana
60. a Please do remember that you are dealing with a coded mask instrument not with a focussing telescope and a CCD It is not possible to deal with one source at a time each source is background for the others the whole field of view and not just the few pixels around your source matters In this Section we guide you through your first IBIS analysis but please read also Section 8 where more details on the main parameters are given You could end up with fake sources that are created by a blind use of parameters More tips and tricks are given in Section 9 for advanced users In the example below we analyze observations of the Galactic Center using data we have downloaded and installed as it is described in Section 6 1 Create the Observation Group with the og_create program see its description in the Toolbox section of 1 cd REP BASE PROD og_create idxSwg isgri_gc lst ogid isgri gc baseDir instrument IBIS As a result of the og_create command the directory REP BASE PROD obs isgri gc is created In this directory you find all you need for the analysis its structure is illustrated in Figure 11 REP BASE PROD obs isgri gc SCW og ibis fits swg idx ibis fits 0051004X0010 001 Observation Group Index of swe_ibis fits Science Window Groups Science Window Group Figure 11 Structure of the directory created with og_create 7 1 Image Reconstruction The first thing to do when you are looking for the first time
61. a gaps The resulted GTIs are written to the IBIS GNRL GTI see details in Table 42 Index of all IBIS GNRL GTI Data Structures for all categories is written to the IBIS GNRL GTI IDX Table 42 Content of IBIS GNRL GTI Data Structures Column Name Description OBT_START On board time of start of the GTI OBT_END On board time of end of the GTI ISDC IBIS Analysis User Manual Issue 5 1 89 C 3 ibis dead This script calculates the dead times for ISGRI PICsIT and Compton cases The results of the executables are written to Data Structures ISGR DEAD SCP PICS DEAD SCP and COMP DEAD SCP This Data Structures contains the information about the on board time and the dead time for each module see Tables 43 45 Table 43 Content of ISGR DEAD SCP Data Structures Column Name Description OB TIME On board time IL DEADTIME 0 Dead time for module 0 ILDEADTIME 1 Dead time for module 1 ILDEADTIME 2 Dead time for module 2 ILDEADTIME 3 Dead time for module 3 ILDEADTIME 4 Dead time for module 4 IL DEADTIME 5 Dead time for module 5 ILDEADTIME 6 Dead time for module 6 ILDEADTIME 7 Dead time for module 7 Table 44 Content of PICS DEAD SCP Data Structures Column Name Description OB TIME On board time IP DEADTIME O0 Dead time for Semi module 0 IP DEADTIME 1 Dead time for Semi module 1 IP DEADTIME 2 Dead time for Semi module 2 IP DEADTIME 3 Dead time for Semi m
62. ad 1 default value The input pixel count is spread between different output map pixels This method is better for the source position estimate but is less accurate than the previous method for source flux estimation SNR in the new spread mosaic will be lower than in the previous case It is possible to decide whether you want the mosaic to be created along with the Science Window image reconstruction or if you prefer it to be created later on The mosaic production is controlled by the OBS1_DoPart2 parameter e OBS1 DoPart2 0 The mosaic step is not performed and the imaging part ends after the Science Window based part e OBS1 DoPart2 1 default value The mosaic is done after the Science Window image reconstruction in the same run ISDC IBIS Analysis User Manual Issue 5 1 36 e OBS1_DoPart2 2 The mosaic is performed for images obtained from different already existing runs see 9 3 1 8 2 3 Background Subtraction In the current OSA you have background maps provided by the ISGRI team These maps are created on the base of observations containing only faint sources in their fields of view Currently a single set of maps for the complete mission is available meaning that background variations are not taken into account In most cases background subtraction improves the result nevertheless we cannot state a priori in which cases the background subtraction will improve or worsen the results The best approach is to verify
63. al pointing duration is of order of 20 minutes e Slew Period during which the spacecraft is manoeuvred from one stable position to another i e from one pointing to another ISDC IBIS Analysis User Manual Issue 5 1 xiii 1 Introduction The IBIS Analysis User Manual i e this document was edited to help you with the IBIS specific part of the INTEGRAL Data Anaysis A more general overview on the INTEGRAL Data Analysis can be found in the Introduction to the IN TEGRAL Data Analysis 1 For the ISGRI and PICsIT analysis scientific validation reports see 3 and 4 The IBIS Analysis User Manual is divided into two major parts e Description of the Instrument This part based to some extent on the ISOC AO 2 document 2 introduces the INTEGRAL on board Imager IBIS e Description of the Data Analysis This part starts with an overview describing the different steps of the analysis Then in the Cookbook Section several examples of analysis and their results and the description of the parameters are given Finally the used algorithms are described A list of the known limitations of the current release is also provided In the Appendix of this document you find the description of the Raw and Prepared Data and also the description of the Scientific Products If you are interested in Data Structures not described in the Appendix go to the ISDC web page http isdc unige ch index cgi Data templates ISDC IB
64. al to the part of each input map that participates in the sum Off axis maps are also weighted by a power law spectrum with the default slope 2 and ARF if present After rebinning off axis maps are normalized to 1 Output energy bands are defined from the index of detector shadowgrams ISGR DETE SHD of a given type Table 14 ii map rebin parameters included into the main script Name Name Type Description in the main script executable corrDol inpCorrDol string DOL of the isgri off axis corrections default rebinned_corrDol_ima rebCorrDol string DOL of the rebinned isgri off axis corrections for imag ing default rebinned corrDol spe rebCorrDol string DOL of the rebinned isgri off axis corrections for spec trum default rebinned corrDol lcr rebCorrDol string DOL of the rebinned isgri off axis corrections for lc default rebinned_backDol ima rebBkgDol string DOL of the rebinned isgri background corrections for imaging default rebinned_backDol_spe rebBkgDol string DOL of the rebinned isgri background corrections for spectrum default rebinned backDolcr rebBkgDol string DOL of the rebinned isgri background corrections for lc default SCW1_BKG_LisgrBkgDol inpBkgDol string DOL of the isgri background model default 12 6 ibis background cor This script combines executables which fill the dead z
65. all lcr fits 1 1c GRS1758 iilight lc fits emin 20 lcselect E MAX 40 instrument ISGRI GRS1758 iilight lc fits contains the merged lightcurve of GRS 1758 258 in the 20 40 keV band that of course has to exist in the lcr fits original files To display it is is convenient to use the lcurve program of the FTOOLS package as shownin Section 7 3 2 9 10 Timing Analysis without the deconvolution Read this if you are interested in fast variability studies up to milliseconds In this section we describe a way of doing timing analysis in a non binning way i e starting from the single events This way is suitable for very short time scales up to milliseconds and is less recommended for long time bins for which the binning tools ii light and ilc extract are suitable In the text we will use one of the Science Windows with Crab data you have downloaded to run the PICsIT analysis e g 003900020020 In general the table with the events is very big so if you are interested in only part of the Science Window e g in the case of a burst it is better to define a user good time interval see Section 9 and work within it To select the photons that come from a given source in the field of view you need to have the corresponding PIF PIF is automatically created during the SPE step but can also be created with a standalone tool i2 pif Create with og create observational group REP_BASE_PROD obs crab og ibis fits and run analysis from
66. also used in FTOOLS http heasarc gsfc nasa gov ftools Each parameter is characterized with a letter that specifies the parameter type i e q query parameters are always asked to the user h hidden parameters are not asked to the user and the indicated value is used learned parameters are updated with the user s value during the use of the program The GUI is a fast and easy way to change the parameters see section 6 3 1 for details e What are groups and indices The ISDC software makes extensive use of groups and indices While it is not necessary to grasp all the details of these concepts a basic understanding is certainly quite useful As implied by their names groups make possible the grouping of data that are logically connected Groups can be seen as a kind of data container not completely unlike standard directories At ISDC we create separate groups for each pointing in which we store the many different data types produced by Integral and its instruments The user then only has to care about one file the group many tens of files being silently included Several pointings the Science Window Groups can be arbitrarily grouped into bigger groups the Observation Group to select data very efficiently according to the user s needs Indices are a special kind of groups which differ only in the fact that all the the data sets they contain are similar and that the indices know the properties of t
67. ations of the gain transforms channels to energy See Section 12 1 for more details GTI Good Time Handling Generates selects and merges Good Time Intervals GTI to produce a unique GTI that is then used by the software to select good events See Section 12 2 for more details DEAD Dead Time Calculation Calculates the total dead time during which the incoming photons may be lost due to the processing of the previous events Also veto strobe signals generated by BGO Bismuth Germanate shield calibration source and Compton events are taken into account See Section 12 3 for more details BINI Event Binning for Imaging Sorts data into energy bins For each energy range the intensity shadowgram and a corresponding efficiency map are created See Section 12 4 for more details BKG Background Correction Creates rebinned maps for background and absorption of support mask see Section 3 2 1 corrections Corrects for efficiency and subtracts background See Section 12 6 for more details After these steps the high level analysis is performed e The second script ibis obs analysis takes the whole Observation Group previously created as input and performs the following tasks CAT_I Catalog Source Selection for Imaging Selects from the given catalog a list of sources in the Field of View matching the criteria defined by script parameters and creates an output list with location and expected flux values of
68. ave discussed in Section 7 1 2 all found new sources are fake ones so remove them with the help of the fv command and make the resulting catalog read only this is important because the file could otherwise get corrupted during the analysis chmod w specat fits The resulting specat fits catalog is shown in Figure 19 only a few selected columns are shown The same ISDC IBIS Analysis User Manual Issue 5 1 28 jU1700 377 scwlc fits FLUX count s 60 40 20 1169 96 1170 1170 02 1170 04 1170 06 1170 06 TSTART T STOP 2 Figure 17 4U 1700 377 science window per science window lightcurve in the 20 40 keV energy band ISDC IBIS Analysis User Manual Issue 5 1 29 Figure 18 Page of IBIS GUI for Spectral and Ligtcurve extraction Figure 19 List of sources used for spectral analysis ISDC IBIS Analysis User Manual Issue 5 1 30 catalog will be used later for the lightcurve extraction In the GUI set the SCW2_cat_for_extract parameter to point to specat fits 1 and press Ok the window disappears and you are back to the main GUI page Press Save and then Run 7 2 1 Results of the Spectral Extraction Spectra are produced for each science window scw 0051004X0010 001 isgri_spectrum fits X 1 5 In these files you find the spectra of the desired sources plus the background spectrum In the header of each data structure the Name and ID of each source are given and the first ex
69. be used only for staring observation where the difference between all the pointings is less than the value defined by the tolerance parameter In this case the corrected shadowgrams are integrated before the deconvolution If staring no then deconvolution will be performed for each science window individually The science windows we use in the current example were observed in staring mode so check the staring button 16The IBIS data mode can be checked in the archive by selecting IBIS mode column on the page with additional parameters 1714 is also possible to select any other energy band but in this case it is up to you to generate and use the proper background maps If you really want to change the energy bands press the hidden button and go to BIN_I page ISDC IBIS Analysis User Manual Issue 5 1 50 Iv 00000 E POINTING 1 1 o0 ey 0 a Figure 24 PICsIT page of the IBIS GUI ISDC IBIS Analysis User Manual Issue 5 1 51 OBS1 ScwType POINTING means that only pointings not slews will be treated SCW1_BKG_P_method defines the way to normalize the background maps to the observed shadowgram before performing the background subtraction O means scaling with exposure and 1 means scaling with the average counts value over the whole detector Both generally provide the same results though the second method which serves as default is sometimes a bit better PICSIT_inCorVar defines w
70. binned_corrDol_ima rebinned_corrDol_spe rebinned corrDol lc rebinned_backDol_ima rebinned_backDol_spe rebinned backDol lc GENERAL clobber GENERAL levelList string string string string string string string boolean boolean DOL of the isgri off axis corrections default DOL of the rebinned isgri off axis corrections for imag ing default gt DOL of the rebinned isgri off axis corrections for spec trum default DOL of the rebinned isgri off axis corrections for lc default DOL of the rebinned isgri back corrections for imaging default gt DOL of the rebinned isgri back corrections for spec trum default DOL of the rebinned isgri back corrections for lc default Clobber existing output data default YES List of all levels default COR GTI DEAD BIN I BKG I CAT I IMA IMA2 BIN S SPE LCR COMP CLEAN Parameters to define which part of data should be analyzed SWITCH disablelIsgri SWITCH disablePICsIT SWITCH disableCompton SWITCH osimData boolean boolean boolean boolean Disable ISGRI analysis possible values YES NO default NO Disable PICsIT analysis possible values YES NO default YES Disable Compton analysis possible values YES NO default YES Data are from simulator possible values YES NO default NO Parameters for ibis binning and ibis image reconstruction IBIS II Chan
71. curves and spectra 9 3 1 Creating a mosaic from different observation groups Suppose you want to analyse 5 Science Windows and are not interested in the final mosaic You create the group with og create and then you launch the analysis till the imaging step but without the mosaic step i e from COR till IMA with OBS1 DoPart2 0 see 8 2 2 An image is created per Science Window but you do not have the overall final mosaic If you then change your mind and decide that you want the mosaic all you have to do is move in the working directory REP BASE PROD obs xxx and relaunch the ibis science analysis command with startLevel IMA endLevel IMA and OBS1 DoPart2 1 This is relatively simple because all the Science Windows belong to the same group so combining the results is trivial But if this is not the case i e if you have run different sets of analysis each one with its own og create command then you need to make some intermediate steps You basically need to create a file that points to all the Science Windows you want to co add We call this file an index To create an index make a list of the Science Window groups you want to combine and save it as e g dols txt To ensure a proper work of the software give the full path i e your file should look like WORKING DIR obs GROUP1 scw 011901070010 001 swg ibis fits 1 WORKING DIR obs GRPUP1 scw 011901080010 001 swg ibis fits 1 WORKING DIR obs GROUP2 scw 012000360010 001 swg
72. dLevel LCR GENERAL_levelList COR GTI DEAD BIN_S LCR again with SCW2_cat_for_extract equal to specat fits 1 e If you are familiar with the sources of your field i e you have already run the imaging part for instance and you want to extract images spectra and lighturves in one go set SCW2_cat_for_extract equal to specat fits 1 and run your analysis with startLevel COR endLevel LCR and the complete list of levels in GENERAL_levelList 8 2 Imaging Source detection is an important and delicate process as the background and all the sources especially the bright ones in the field of view will have an impact on it Because of this intrinsic complexity of the instrument there are different options as far as source search and background correction are concerned The choice of the best method to use for a given case may require a bit of iteration on your side In the next two paragraphs we describe the parameters involved in the source search along with some practical advices The single Science Window case is treated in Section 8 2 1 while the mosaic image case in Section 8 2 2 Comments on the background subtraction issue are given in Section 8 2 3 while a set of miscellanea on imaging parameters is given in Section 8 2 4 8 2 1 How to choose the source search method in the Science Window analysis Basically the idea is that you can either let the software look for the excesses in the field or you can tell the software to loo
73. data can be commanded from ground The time resolution can take values between 1 and 500 ms the current default is 500 ms and two energy channels but the values to be used for routine observations will be decided when the in flight background of PICsIT is measured and compared with the available telemetry rate during the commissioning phase ISDC IBIS Analysis User Manual Issue 5 1 12 In Table 2 the properties of the all modes are summarized Table 2 Characteristics of the IBIS Telemetry Formats Detector Image Timing Spectral Observing Mode Resolution Resolution Resolution pixels channels ISGRI photon by photon 128x128 61 035us 2048 PICsIT Photon by Photon 64x64 64us 1024 Spectral Imaging 64x64 X 30 min 256 Spectral Timing None 1 500ms 2 8 ISDC IBIS Analysis User Manual Issue 5 1 13 Part II Cookbook This Part was completely rewritten by M Chernyakova A Paizis I Lecoeur Taibi ISDC IBIS Analysis User Manual Issue 5 1 14 5 Overview In this Section an overview of the analysis of IBIS data is given Each photon detected by IBIS is analyzed with the on board electronics and tagged with the arrival time type ISGRI PICsIT Compton etc energy position etc according to the operation mode i e photon by photon standard calibration etc These data are then sent to ground in telemetry TM packets During Pre Processing the TM packet informati
74. de shielding from the diffuse background in the gaps between the mask edges and the top of the tube walls 3 2 3 Detector The ISGRI CdTe and PICsIT CsI TI detectors are layered with respect to each other with PICsIT below ISGRI with respect to the coded mask and hence the astronomical source e Upper Detector Layer ISGRI Cadmium Telluride CdTe is a semiconductor operating at ambient temperature 0 20 C is the optimum range With their small area the CdTe detectors are ideally suited to build an image with good spatial resolution ISDC IBIS Analysis User Manual Issue 5 1 8 ISGRI PICsIT composed of CdTe crystals composed of Cs1 crystals 128 32 32 64 16 Figure 7 ISGRI and PICsIT division in modules and submodules The CdTe layer is made of 8 identical Modular Detection Units each having 32x64 pixels see Figure 7 Total sensitive area of the detector is 2621 cm e Lower Detector Layer PICsIT Caesium Iodide is a scintillation crystal The CsI T1 layer is divided into eight rectangular modules of 16x32 detector elements see Figure 7 In each module there are two independent semi module each one with its independent Front End Electronics Total sensitive area of the detector is 2994 cm e Noisy Pixels It is possible that with the time some of the pixels of the detector may become out of order and start to produce outputs not triggered by an income photon i e to become noisy If the pa
75. ding pattern of PICsIT mask 12 9 Spectral Analysis 12 9 1 i spectra extract ii spectra extract reads the shadowgram for each each input energy band For each output energy band it ISDC IBIS Analysis User Manual Issue 5 1 77 creates a model PIF for each source The Pixel Illumination Factor PIF is a number between 0 and 1 which expresses the theoretical degree of illumination of each pixel in the detector plane of a coded mask instrument The PIF is calculated on the basis of the position and is normalized to 1 cts pix source fits all source intensities together with a background estimate to the data shadowgrams writes all source estimates to the spectra index Finally ii_spectra_extract writes to the PIF index one mean model per input catalogue source There is a possibility to chose one of several fitting metods The recommended method is iterative imaging like Least Squares fit method 6 In the first step of this method the fit of each source separately in its coded zone is done Next in the second step the calculation of reciprocal source contributions is performed The first step is aimed to decrease the background modelling error influence The second one corresponds to the ghost cleaning Please note that Maximum Likelihood method is not working in standard OSA configuration with isdcmath package In the fitting process the source positions are considered to be exact If the
76. e able to analyse it in XSPEC We suggest to build such a matrix before launching OSA as shown in Section 9 4 and then extract images with the use of this same matrix as shown in Section 9 4 1 See Sections 7 1 and 8 2 2 to learn how to create mosaic images for a better flux estimate use OBS1_PixSpread 0 Once you have the set of mosaic images in the desired energy bands to extract the spectrum from the mosaics attached to the og ibis fits file at the position of 4U 1700 377 ra 255 9865 dec 37 84414 use MOSAQLC_SPEC ISDC IBIS Analysis User Manual Issue 5 1 44 cd REP_BASE_PROD obs xxx mosaic spec DOL_inp 0g_ibis fits 1 DOL out og ibis fits 1 N EXTNAME ISGR MOSA IMA DOL_spec 4U1700_mosa_pha fits ISGR PHA1 SPE tpl ra 255 9865 dec 37 84414 size 4 Note that if the significance of the point is less than five then mosaic_spec will assign a non zero value to its quality and the point will be not used by XSPEC If you are interested to see this point do change its quality value to zero manually You find more details on mosaic_spec in Section 12 12 1 9 8 Barycentrisation Read this if you want to apply barycentrisation to an extracted lightcurve The tool making such a correction is called barycent Note that it re writes the input file so it may be worth to copy the original file first Below we show an example for 4U 1700 377 Science Window number 011800900010 and observation group identification ogid para
77. e extraction tools use the source position saved in the RA FIN and DEC FIN columns These are the values computed during the imaging step thus in case you want to use catalog source positions you have to modify them manually In case you prefer the catalog positions for all catalog sources you can remove RA FIN and DEC FIN columns RA_OBJ and DEC OBJ are used then with the following commands chmod w specat fits fdelcol infile specat fits 1 colname RA FIN confirm no proceed yes fdelcol infile specat fits 1 colname DEC FIN confirm no proceed yes chmod w specat fits Important make the file with the catalog read only otherwise it may be corrupted in the course of the analysis ISDC IBIS Analysis User Manual Issue 5 1 38 9 Useful recipes for the ISGRI data analysis In this Section we give a number of recipes that can be useful in the analysis of ISGRI data 9 1 Rerunning the Analysis Read this if you would like to redo part of your analysis e g if your run has crashed or if you want to change some parameters In case you want to re run the analysis with different parameters run og_create but this time with a different ogid parameter This will create a new tree under obs ogid where all the new results will be stored If the pipeline has crashed in general it is safer to restart your analysis from scratch removing the obs ogid directory and restarting from the og create step In any case we give below a set of recip
78. e merged for ISGRI default GTIs to be merged for PICsIT default VETO ATTITUDE P SGLE DATA GAPS P_MULE_DATA_GAPS GTIs to be merged for ISGRI default VETO ATTITUDE ISGRI DATA GAPS DOL of a bad time interval table GNRL INTL BTI default gt Input BTI names to be considered default DOL of the index of pixels switches list default DOL of the gain offset table default gt DOL of the rise time correction table default DOL of the IC file for calibration parameters default Probability of shot time decay default 0 01 DOL of the energy correction table PICsIT default gt Cleaning of cosmic ray induced events possible values 0 No 1 Yes default 1 DOL of the IC file for VETO model and width of Compton window default DOL of the index of noisy maps default gt index of Low Threshold default DOL of the dead time data structure default ISDC IBIS Analysis User Manual Issue 5 1 102 SCWI BIN P inGTI string DOL of the good time interval data structure default SCWI BIN P HepiLut string DOL of the hepi lut default SCW1_BKG_divide boolean Divide by efficiency Do not touch it default no SCW1_BKG_badpix boolean Remove bad pixels Do not touch it default yes SCW1_BKG flatmodule boolean flatten modules Do not touch it default no SCW1_BKG_Lisg
79. e of event Corrected Data Structure Photon ISGRI I ISGR EVTS COR PICsIT single PS PICS SGLE COR by PICSIT multiple PM PICS MULE COR Compton single CS COMP SGLE COR photon Compton multiple CM COMP MULE COR Spectral Imaging PICsIT single PICS SISH COR The content of the level COR Data Structures for the photon by photon mode is given in Table 40 The abbreviations for the events types are taken from Table 39 Table 40 Content the level COR Data Structures for the photon by photon mode Column Name Description Event Type ISGRI PI corrected rise time for ISGRI LCS CM ISGRLENERGY Deposited energy in the ISGRI layer LCS CM PICSIT ENERGY Deposited energy in the PICsIT layer PS PM CS CM SELECT FLAG Selection flag shows whether the event was I CS CM noisy 1 or not 0 The PICS SISH COR Data Structure for spectral imaging mode contains the total number of counts measured by each detection unit in each energy channels The time information is in the index PICS SISH COR IDX see Table 41 for details Table 41 Content the PICS SISH COR IDX Data Structure Column Name Description OBTSTART OBT start of integration OBTEND OBT end of integration HIST NUM Histogram number HIST ID Histogram identifier MEM AREA Histogram memory area C 2 ibis gti This script builds Good Time Intervals from housekeeping data information about satellite stability and dat
80. e program cd ibis_data_rep setenv REP_BASE_PROD PWD og_create idxSwg staring lst ogid picsit_ima baseDir instrument IBIS cp r obs picsit_ima obs picsit_spe ISDC IBIS Analysis User Manual Issue 5 1 48 Bin time 0 1000E 02 s Power ex a o 3 4 4 x x 4 ou oso ue ide po gs gp ge de gt jc qd Wo 0 50 100 150 200 250 Frequency Hz Start Time 12866 15 57 30 185 Stop Time 12866 16 33 53 323 Figure 22 Crab power spectrum 10 1 PICsIT Image Reconstruction To start the analysis go to the working directory REP_BASE_PROD obs picsit_ima and call the ibis_science_analysis script cd obs picsit_ima ibis_science_analysis After a few seconds the main page of the IBIS Graphical User Interface GUI appears as shown in Figure 23 Press Reset button to be sure that you have the default ISDC_ENV parameters For PICsIT there were no major changes since the creation of revision 2 data so you can start directly from the BIN I level startLevel BIN I The end level for PICsIT image creation should be the default endLevel IMA2 Disable ISGRI analysis by checking SWI TCH_disablelsgri button and enable PICsIT by unchecking SWITCH_disablePICsIT button PICsIT operates in an energy range 0 175 10 MeV where background subtraction plays a very important role The OSA for PICsIT provides a default set of maps for the background subtraction in certain energy bands selected to optimize the instruments performa
81. e returned and not e g slews Put gt 2003 03 15 23 00 00 in the field start_date and put lt 2003 03 16 02 30 00 in the field end_date Put public in the field ps to specify that only public ScWs should be returned Put gt 100 in the field good_isgri to select Science Windows with good ISGRI time higher than 100 seconds Press the Start Search button at the bottom of the web page In our case a table with 5 ScWs will be displayed Select the SCWs of interest To follow the example in the Cookbook click on All for all SCWs Press the Save SCW list for the creation of Observation Groups button at the bottom of that table and save the file with the name isgri_gc lst This file isgri_gc Ist will be used later as input for the og_create program see Section 7 From this file you need the 5 lines scw 0051 005100410010 001 swg fits 1 scw 0051 005100420010 001 swg fits 1 3When an analysis script asks you to specify the DOL you should specify the path of the corresponding FITS file and the corresponding name or number of the data structure in square brackets do not forget that numbering starts with 0 See more details in the Introduction to the INTEGRAL Data Analysis 1 Please note that the naming scheme is different for revision 1 and revision 2 data For the revision 1 data the name of the prepared Science Window Group is swg_prp fits instead of swg fits ISDC IBIS
82. e will be created OBS1_DoPart2 1 In this mosaic image the photons belonging to a source are spread around the single central peak OBS1_PixSpread 1 resulting in better source location Now that you have checked all the parameters press Ok the Imaging window disappears and you are back to the main GUI page Press Save and then Run SIMA2 level is for PICsIT analysis only and there is no difference for ISGRI analysis whether endLevel is set to IMA or IMA2 ISDC IBIS Analysis User Manual Issue 5 1 24 204060 100 40 60 100 200 Figure 13 Imaging page of IBIS GUI 7 1 1 Results from the Image Step When the analysis is finished you will find that new files have appeared in your working directory In Figure 14 an overview of the files related to the image reconstruction is given The full description of all files produced at different levels is given in Appendix C As it is shown in Figure 14 there are results for each science window as well as for the overall group Science window results include e Images scw 0051004X0010 001 isgri sky ima fits X 1 5 for each energy range four images are produced intensity variance significance and residual To know which type of image and which energy band correspond to a given extension you can either check in the header of the isgri sky ima fits files or check the first extension of the file an index summarizing the file content see Figure 15 More d
83. ePars default 1 ISDC IBIS Analysis User Manual Issue 5 1 104 ISGRI_mask string DOL of the MASK pattern fits file default OBS1_deco string DOL of the projected decoding pattern fits file default gt OBS1 tungAtt string DOL of the Tungsten attenuation length fits file default gt OBSI aluAtt string DOL of the Aluminium attenuation length fits file default OBSI leadAtt string DOL of the Lead attenuation length fits file default OBS1_covrMod string DOL of the covariance fits file default OBS1_ScwType string Type of Science Window to be treated possible values POINTING SLEW OTHER t ANY default POINTING OBS1_DoPart2 integer if 1 or absent do mosaic part Set it to 0 if don t want to produce a mosaic image Set it to 2 if you want to produce a mosaic image from different existing runs default 1 OBS1_MapAlpha real Mosaic map center deg default 0 0 OBS1_MapDelta real Mosaic map center deg default 0 0 OBS1_MapSize real Mosaic map radius deg default 40 0 OBS1_PixSpread integer 0 no flux spread in mosaic default 1 OBS1_MinCatSouSnr real The software detects a catalog source only if its signal to noise ratio is higher than this value default 6 OBS1_MinNewSouSnr real The software detects a catalog source only if its signal to noise ratio is higher than this value default
84. eV one ISDC IBIS Analysis User Manual Issue 5 1 40 1 index_comb fits and then replace the first row of og_ibis fits 1 automatically with cd REP_BASE_PROD obs GROUP1 fmodtab og_ibis fits 1 MEMBER_LOCATION modfile fdelrow og_ibis fits 1 2 1 N Y rm isgri_catalog fits With the fdelrow command you detach from the first extension of og ibis fits row number 2 the first row to be deleted number of rows to be deleted 1 you were shown no keyword values N and you agreed to proceed Y This second row contained the catalog that was created in previous run during CAT step and contain only sources that were in the field of view of science windows from GROUPI To have a common catalog for GROUP1 and GROUP2 it would be necessary to rerun CAT I step for the group referring to all science windows of interest You may check with fv that actually the first row of og ibis fits is indeed index comb fits Before running the mosaic step please be aware that e If you had previously run the mosaic step you will see that og ibis fits points to the mosaic output af ter you have deleted a reference to isgri catalog fits rows 2 to 4 of the first extension are isgri srcl res fits isgri mosa ima fits and isgri mosa res fits This will interfere with the new mosaic you are about to launch thus you have to detach these former mosaic results from the group and delete or rename them cd REP BASE PROD obs GROUP1 fde
85. ead attenuation length fits file default gt Type of Science Window to be treated possible values POINTING SLEW OTHER ANY 22 default ANY if 1 or absent do mosaic part Set it to O if you don t want to produce a mosaic image default 1 Mosaic map center deg default 0 0 Mosaic map center deg default 0 0 Mosaic map radius deg default 40 0 0 no flux spread in mosaic default 1 Software detects the catalog source only if its signal to noise ratio is higher then this value This parameter has no meaning for the Science Window level images if OBS1 SearchMode 1 3 default 6 Software detects a new source only if its signal to noise ratio is higher then this value default 7 0 for fitting source position and 1 for fixed source po sition in Scw fit default 0 76 OBS1_ExtenType ExtenType integer exposure residual maps possible values 0 or absent Residual Map at 4 n th extension of ima idx 1 Exposure Map only at 4 n th extension of ima idx 2 both Residual and Exposure maps at 4 5 n th ex tension of ima idx 3 one Expo map at the end of ima idx if ExtenType 1 2 3 the Mosaic Exposure Map at 4 n th extension of mosa idx default 0 OBS1_NegModels NegModels integer 0 or absent for no negative models 1 negative models default 0 OBS1_FastOpen FastOpen integer if 1 then no CommonPreparePars default 1
86. ee 10 IBIS sensitivities for the various detection techniques lll 12 Science Analysis Overview ee 15 Structure of the directory created with og create eee 23 Main page of the IBIS GUI 225 ee Ree Rodeo x OR Se OR RR m9 dE d 24 Imaging p peofIBIs GUL 222 2x 99 gb R a UE ODES A RU x 25 Overview of the IMA level products a 26 Sketch of the isgri sky ima fits structure left and extract from the Index table right 27 Intensity left and significance right mosaic in the 20 40 keV energy band 28 4U 1700 377 science window per science window lightcurve in the 20 40 keV energy band 29 Page of IBIS GUI for Spectral and Ligtcurve extraction lee 30 List of sources used for spectral analysis eee 30 Total AU 1700 377 specifi oclo om m9 ooo odes a eu 32 4U1700 377 fits lightcurve in 20 40 keV energy range with 100 sec binning 34 Crab power Spectator vo ee ee Ee ee e a 49 Main page of Che IBIS QUE 2c s om He Re RR RR ORO 50 PICSIT passo the IBIS GUL 215a oque AR ARA um oe eae SE ea 51 Crab significance image in the 252 336 keV energy band as seen by PICSIT 53 PICsIT Crab spectrum extracted from the mosaic 2e 54 PICsIT Crab spectrum created as described in Section 10 3 56 Composition of the main script ibis science analysis For further descriptions of the BIN BKG steps for the DEAD IMA and BIN S leve
87. element dols txt index index comb 2 fits 1 Then run lc pick and spe pick putting the parameter group equal to index comb 2 fits 1 cd REP BASE PROD obs lc pick source GRS 1758 258 attach n group index comb 2 fits 1 lc GRS1758 1c fits emin 20 lcselect E MAX 40 instrument ISGRI GRS1758 lc fits contains the merged lightcurve of GRS 1758 258 in the 20 40 keV band energy range that of course has to exist in the isgri lcr fits original files cd REP BASE PROD obs spe pick group index comb 2 fits 1 N source GRS 1758 258 rootname GRS1758 instrument ISGRI GRS 1758 sum pha fits the combined spectrum of GRS 1758 258 and GRS1758 single pha2 fits a file with the four spectra of the initial four Science Windows collected together are created It is forseen that in the nearest future there will be several ARFs depending on the data time In order to deal with the data from different time periods spe pick was updated and creates now a resulted ARF for your particular dataset This ARF is written to GRS1758 sum arf fits and GRS1758_single_pha2 fits files The names of the response and ancrfile are inserted in the keyword of the final files so that they are automatically recognised by XSPEC 9 4 Rebinning the Response Matrix Read this if you want to use a spectral binning different from the default one You will also learn how to rebin the response matriz to extract images in more than 10 energy ranges
88. empty then it is taken from the imaging result of the Science Window default Name of the column where to get Ra default RA FIN Name of the column where to get Dec default DEC FIN Catalog for PICsIT imaging default gt filter to apply on the source default gt CFITSIO event selection string default parameter for building light curves from PICSIT spectral timing data Parameters for spectra extraction ISDC IBIS Analysis User Manual Issue 5 1 106 IBIS_SI_ChanNum IBIS_SI_E_band_min IBIS_SI_E_band_max IBIS_SI_inEnergy Values PICSIT source name PICSIT source RA PICSIT source DEC IBIS_SS_inEnergy Values IBIS SM inEnergy Values IBIS SP ChanNum IBIS SP E band min s IBIS SP E band max s IBIS SP E band min m IBIS SP E band max a IBIS SPS ChanNum IBIS SPS E band min s IBIS SPS E band max s integer string string string string real real string string integer string string string string integer string string Number of Channels possible values 1 10 1 take from ISGR EBDS MOD structure default 1 List of lower limits of output energy bands default gt List of upper limits of output energy bands default DOL of the energy values when required default Name of the source for extracting PICsIT spectrum defau
89. en correct if not 2 then don t correct 4 if we cannot determine either 2 or not 2 then flag As a result the TIMECORR keyword can have the following values 0 no possible jump 1 possible jump jump indeed exists corrected 2 possible jump jump did not take place not corrected 3 possible jump cannot decide if jump took place not corrected 4 possible jump algorithm has a problem to be investigated If you are doing absolute timing and your data contains TIMECORR gt 0 take great care If TIMECORR 1 or 2 it should be OK If TIMECORR 3 you should better not use it If TIMECORR 4 contact ISDC 7 The lightcurve extraction ii lc extract program is performed by building shadowgrams for each time and energy bin It potentially takes a large amount of CPU time and moreover there is a limit on the minimum duration of the time bins for a given number of energy bins and the duration of the given Science Window The time bin for the light curve must be such that the total number of maps in the file isgr corr shad does not exceed 2 Gig worth of disk space Since 3 maps intensity variance efficiency are created per image and each image takes 130 134 4 bytes or 24 fits blocks plus one fits block for the header for a total of 3 25 2880 216000 bytes the product of the number of time bins per each science window and the number of energy bands must be less than about 9942 assuming that no images are left from image and spectral analysi
90. es 1 radial width frozen as input 0 radial width left free 1 x and y width left free 2 x and y width fixed as found for first band default 2 ISDC IBIS Analysis User Manual Issue 5 1 81 outmode integer Choose data for output posible values 1 intensity from the most significant pixel 2 fitted intensity default 2 psf real HWHM of PSF in arcmin possible values 0 1 20 default 6 size integer h 20 1 1000 Enter source box half size in pixels on which the fit is performed possible values 1 1000 default 20 back boolean Should a constant intensity background be considered in the fit default no allEnergies boolean Enter if the program has to select automatically energies default yes emin string Enter vector of energy bands minimum default 25 30 40 chatty integer Enter reporting level 10 includes MINUIT log possible values 0 10 default 4 12 12 2 ilight For every PIF found in the Science Window di light extracts simultaneously a lightcurve for each source and one light curve for background in all specified energy bands Dead pixel data gaps off axis correction energy low threshold and illumination factors are taken into account The method used is a fit of hyperplane through the cloud of points formed by the number of counts versus PIF fraction for every source In the case of one source this is just a linear regression The intercept give
91. es that can be useful Because of the group concept you cannot just delete the result you do not like and restart the pipeline All results that were produced in the course of the analysis are linked to the group and should be detached before you relaunch the script To do this you can use the og_clean program that will clean an Observation Group up to the level specified with parameter endLevel All data structures with a level equal or prior to endLevel will be kept while the data structure with a later level will be erased For example to run the spectral extraction SPE level you should clean from group whatever comes after the BIN S level as this is the level immediately preceeding the spectral one see Fig 12 og clean ogDOL 0g_ibis fits 1 endLevel BIN S If og clean fails it could be due to the fact that the group was corrupted You should try to fix it with dal_clean program dal clean inDOL og ibis fits 1 checkExt 1 backPtrs 1 checkSum 1 and launch og clean only afterwards Unfortunately the current version of og clean is very slow In some cases if you know exactly which data structure has to be detached it would be much faster to launch dal detach For example if you run your analysis till SPE or LCR level and would like to produce a mosaic image afterwards you do not have to clean the group deleting all your results but just have to detach ISGRI SRCL RES data structure note that with the option delete y a
92. etails on index concept are in 1 e Detected source list scw 0051004X0010 001 isgr sky res fits X 1 5 list of the sources detected in each energy range with reconstructed RA DEC flux error and signifi cance Observation group results include e Images isgri mosa ima fits The structure of this file with the mosaic images is similar to the one of isgri sky ima fits but instead of residual maps you have the exposure ones e Detected source list isgri mosa res fits list of the sources detected in the mosaic image in each energy range with reconstructed RA DEC flux error and significance The single science window and mosaic results are merged in the file isgri_srcl_res fits This file contains all the sources from the isgri catalog fits plus all the new sources with the information on their fitted position fluxes and detection level Note that systematic errors are not included in the calculation of the detection significance DETSIG 8The intensity image from which all photons attributed to the detected sources were removed ISDC IBIS Analysis User Manual Issue 5 1 25 REP_BASE_PROD isgri_catalog fits obs isgri gc sew isgri mosa ima fits isgri mosa resfits isgri srcl resfits i E Nepot Catalog x Be createa at CAT I step A 005 1004X00 10 001 x set of mosaic images Out i List of sources BREE found in the 2 E M B mosaic image isgri sky ima fits isgri sky res fits A se
93. ethodFit integer Method to be applied for background and source in tensity fitting default 6 SCW2_ISPE_isgrUnifDol string DOL of the ISGRI detector uniformity default SCW2 ISPE tungAtt string DOL of the Tungsten attenuation length fits file default SCW2 ISPE aluAtt string DOL of the Aluminium attenuation length fits file default SCW2_ISPE_leadAtt string DOL of the Lead attenuation length fits file default SCW2_BIN_cleanTrk integer Cleaning of cosmic ray induced events possible values 0 No 1 Yes default 0 SCW2 BIN L idxNoisy string DOL of the index of noisy maps default SCW2_BIN_LidxLowThre string index of Low Threshold default SCW2 BIN P inDead string DOL of the dead time data structure default SCW2 BIN P inGTI string DOL of the good time interval data structure default SCW2 BIN P HepiLut string DOL of the hepi lut default ISDC IBIS Analysis User Manual Issue 5 1 108 SCW2 BKG LisgrBkgDol string DOL of the isgri bckg model or if you want none or empty if you want DOL automatic from the IC tree default SCW2_BKG divide boolean Divide by efficiency default no SCW2_BKG_badpix boolean Remove bad pixels default yes SCW2_BKG flatmodule boolean flatten modules default no SCW2_BKG_I_method_cor string Method to be applied for background removal default 0 SCW2_BKG_I
94. f the event involves detection units of both ISGRI and PICsIT The application of Compton reconstruction algorithms to these types of events between few hundred keV and few MeV allows an increase in signal to noise ratio attainable by rejecting those events unlikely to correspond to source photons inside the field of view The detector aperture is restricted in the hard X ray part of the spectrum by passive shielding covering the distance between mask and detection plane An active BGO scintillator VETO system shields the detector bottom as well as the four sides up to the bottom of ISGRI Figure 2 shows a cut away drawing of the various components of IBIS except the mask and tube Figure 3 shows the distances between the different parts of the detector assembly Figure 4 shows the spacecraft amp instruments coordinate systems ISDC IBIS Analysis User Manual Issue 5 1 4 __ Hopper _ CdTe layer SGRI t PICSIT Figure 2 Cutaway drawing of the IBIS detector assembly together with the lower part of the collimator Hopper 3502 ar E L 3400 3198 Lis PLM detectr or bench Not to scale fes 3a Spider 7 MESS S eS 3206 w y m PIT x Figure 3 IBIS detector assembly in numbers ISDC IBIS Analysis User Manual Issue 5 1 Spacecraft amp Instrument Coordinate Systems Z Sun 127 127 SCY 1 4
95. ge E MAX Upper bound of the energy range PICSMODE Mode of the PICSIT detector layer Table 57 Content of the PICS EVTS LCR Data Structure Column Name Description TIME Time of measurement for the bin TOT COUNTS Total counts of the source region BACKV Background counts scaled to the source region BACKE Background count errors ERROR Net count error in the source region RATE Countrate in the given energy band FRACEXP Fraction of integration bin time for exposure correction i lc extract For all sources from the isgri srcl_res fits file ii lc extract extracts the ISGRI lightcurves The results are written to the ISGR SRC LCR and ISGR SRC LCR IDX Data Structures ISGR SRC LCR has the same structure as PICS EVTS LCR see Table 57 Table 58 Content of the ISGR SRC LCR IDX Data Structure Column Name Description SOURCEID ISDC unique source identifier RA OBJ Source right ascension in degrees DEC OBJ Source declination in degrees CHANMIN Lowest channel of the energy range CHANMAX Highest channel of the energy range E_MIN Lower bound of the energy range E_MAX Upper bound of the energy range C 9 3 Timing Analysis without the deconvolution During the run of stand alone programevts_extract two data structures GNRL EVTS GTI and GNRL EVTS LST are filled GNRL EVTS LST Table 59 combines all available information for photon by photon events from dif ferent instruments during a given
96. h scw run directory a file ler fits with 4 lightcurves in 20 40 40 60 60 100 100 200 keV energy bands with 10 seconds binning delta t 10 The sources for which a lightcurve is extracted are the ones for which a PIF was created at the SPE level i e specified in SCWSA2 cat for extract see Section 7 2 9 9 3 Merge the ii light results from different Science Windows If you want to merge in one file all the lightcurves provided by ii light for a given source you can use the lc pick tool as shown in Section 9 3 2 ii light is a stand alone tool and does not update the proper files with its results Even if you have run both the lightcurve tools in whichever order only the standard one called within the script LCR step ii lc extract will have updated the proper files with its results i e the swg_ibis fits file Thus if you run lc_pick to collect the lightcurves only the standard ones will be selected If you want to collect the results of ii light then you have to create an index file that points to all the ii light produced lightcurves and then give this file as input to lc pick as shown below ISDC IBIS Analysis User Manual Issue 5 1 46 cd REP_BASE_PROD obs setenv run 0051 dal create obj name all lcr fits template ISGR SRC LCR IDX tpl foreach file 0GID scw run lcr fits idx collect index all lcr fits 1 template element file 1 end lc pick source GRS 1758 258 attach n group
97. hat pha outfil tmp pha exposure CALC ncomments 0 areascal mv tmp pha sum pha echo npha end mathpha units R errmeth gaus expr sum pha npha outfil tmp pha exposure sum pha ncomments 0 areascal mv tmp pha sum pha fparkey value ic ibis rsp pics_srmf_grp_0003 fits fitsfile sum pha keyword RESPFILE fparkey value ic ibis rsp pics_sarf_rsp_0002 fits fitsfile sum pha keyword ANCRFILE Now you are ready to launch xspec and check the resulted spectrum xspec XSPEC gt data sum pha XSPEC gt setplot energy XSPEC gt ign 1000 XSPEC gt plot ldata The result is shown in Figure 27 ISDC IBIS Analysis User Manual Issue 5 1 55 data and folded model sum pha T T T T 0 05 0 02 normalized counts sec kev 0 01 5x10 2x10 7 500 channel energy kev chemyak 1 How 2005 18 17 Figure 27 PICsIT Crab spectrum created as described in Section 10 3 ISDC IBIS Analysis User Manual Issue 5 1 56 10 4 PICsIT Timing Analysis It is possible to produce a lightcurve of the PICsIT detector from the spectral timing data To build it it is enough to run the analysis from the COR to DEAD level and then from LCR to LCR of course it is not a problem if you have already done the analysis up to the IMA2 level Do not forget to disable ISGRI and enable PICsIT for the analysis The results are in the following FITS files scw RRRRPPPPSSSF 001 picsit_lcr fits
98. he 5 0 version Section 9 5 was added Sections 9 3 1 9 4 1 and 9 7 were updated Table 40 was updated 15 November 2005 5 1 Update of the Fifth Release Sections 7 1 2 7 2 8 3 9 3 2 9 9 2 12 2 12 9 11 and the bibliography were updated Section 10 3 12 9 2 and Table 53 were added 24 NOV 2005 Printed ISDC IBIS Analysis User Manual Issue 5 1 Contents Acronyms and Abbreviations e Glossary Of A eee OS RE 1 o ov a Sh a xr EU ee a ee ADD a I Instrument Definition 2 Scientific Performances Summary lr 3 Instrument Description 2 2466 44 ee RR RR EA 3 1 The Overall Design o 9 2 The Subsystems Ciria gone A es 3 2 1 The Mask eR xo Ro ES eG 22 2 The Collmater cocos rar 3 2 9 Debschof 26 ys a he ACACIA 3 2 4 On board Calibration Unit 9 2 5 Veto Slidld sasac ua ora 4550844 RA 4 How the Instrument works 0 4 1 Event Types 2669999 PR E RSS 4 2 IBIS observing modes II Cookbook 5 o fee aid a Gow Oe Gain de du ats 6 Getting Started 562 Pe AA 6 1 Setting up the analysis data 6 1 1 Downloading data from the archive 6 2 Setting the environment 6 3 Two ways of launching the analysis 6 3 1 Graphical User Interface GUI 6 3 2 Launching scripts without GUI 6 4 Useful to know 22 ee eee AAA 7 lt A Walk through ISGRI Analy
99. he collecting merging tools Ic_pick and spe_pick directly on the group group og ibis fits 1 ISDC IBIS Analysis User Manual Issue 5 1 41 If you have Science Windows belonging to different groups you need an intermediate step Basically you need to create a file an index that points to all the Science Windows you want to co add similarly to the case seen in section 9 3 1 Then this file will be given as input via the group parameter at the place of og ibis fits To create the index make a list of the Science Window groups you want to combine and save it as e g dols txt under REP BASE PROD obs To ensure a proper work of the software give the full path i e your file should look like WORKING DIR obs GROUP1 scw 011901070010 001 swg_ibis fits 1 WORKING DIR obs GRPUPI scw 011901080010 001 swg ibis fits 1 WORKING DIR obs GROUP2 scw 012000360010 001 swg ibis fits 1 WORKING DIR obs GROUP2 scw 012000370010 001 swg ibis fits 1 The first 2 files belong to a run with the og create parameter ogid equal to GROUP while the latter two to a run with ogid equal to GROUP remember the 1 t WORKING DIR has to be the extensive name of REP BASE PROD WARNING make sure that the lightcurve and spectra result files exist for each Science Window you want to co add isgri lcr fits and isgri spectrum fits files Then give the command that actually builds the fits file from the ASCII file cd REP BASE PROD obs txt2idx
100. he data sets they contain Indices are a kind of poor man s database For example an imaging program creates several images of different types flux map significance map in different energy bands These images are stored in an index in which the image type and energy band information is replicated ISDC software is then able to select very efficiently the needed images The user can also make use of the indices just by looking at the index for instance using fv the user can identify immediately the content of each image e Why do I need 1 after a FITS file name A FITS file can have many extensions and sometimes it is necessary to specify as input to a given pa rameter not the file name alone file fits but the extension too file fits 1 or file fits 2 etc The file name with a specified data structure extension is called DOL Data Object Loca tor When you modify the parameter file itself see above or use the GUI the extension will be correctly interpreted in the file fits 1 case On the command line though the normal CFITSIO and FTOOLS rules apply i e you have to specify it as one of the following file fitsl 1 file fits 1 file fits 1 Note that if no extension is specified explicitly then the first one 1 will be used by default ISDC IBIS Analysis User Manual Issue 5 1 22 7 A Walk through ISGRI Analysis After setting up as described in the previous section you are ready to analyse the dat
101. hether you would like the software to partially correct the variance shadowgram for systematic effects due to the background value 1 or not in order to estimate by yourself the degree of systematics present in the deconvolved maps value 0 PICSIT_outVarian defines whether you would like to have the variance maps in output value 1 or not value 0 Note that the mosaic executable of the pipeline ip_skymosaic works only in case PICSIT_outVarian 0 Return to the main GUI window by clicking on OK Without changing other default parameters you are now ready to run the analysis do so by clicking on Run 10 1 1 Results of PICsIT image analysis In case of a staring the output images are in file picsit_ima fits For each energy range and each type of event single multiple 2 types of images INTENSITY and SIG NIFICANCE are produced In case PICSIT_inCorVar 1 a variance map is also produced The list of found sources is in the file picsit_sky_res fits In our example the Crab is the only source found In Figure 25 you see the resulting image in the 252 336 keV energy range The Crab is clearly seen in the center The figure was produced with the help of ds9 cat2ds9 picsit_sky_res fits 3 found reg symbol circle color red ds9 picsit_ima fits 5 region found reg cmap cool scale linear scale limits 0 7 zoom 8 In the case of observations with dithering pattern staring no the pipeline performs the shadowgram deconv
102. ibis fits 1 WORKING DIR obs GROUP2 scw 012000370010 001 swg ibis fits 1 The first 2 files belong to a run with the og create parameter ogid equal to GROUP 1 while the latter two to a run with ogid equal to GROUP2 remember the 1 WORKING DIR has to be the extensive name of REP BASE PROD WARNING make sure that obs scw 001 isgri sky ima fits files exist in all the Science Windows you mention otherwise the merging will not work Then give the command that actually builds the fits file from the ASCII file cp dols txt REP BASE PROD obs GROUP1 cd REP BASE PROD obs GROUP1 txt2idx element dols txt index index comb fits 1 The file index comb fits is created and you can look at it with fv In the first extension you have 4 rows each row has the link to a given swg ibis fits file What you need to do now it to let the software know that it has to use this particular set of Science Windows for the analysis You do this by pointing og ibis fits to this file This has to be done because no matter what level of the scientific analysis you are performing the software will analyse the Science Windows pointed to by og_ibis fits Create an ASCII file REP BASE PROD obs GROUP1 modfile with one line in it 14Please note that the images that you intend to merge MUST have the same energy boundaries i e all the SCW maps must have been analysed in the same way You cannot merge a 20 40 keV map with a 30 50 k
103. in O none 0 Name of output file default Do you want to plot your results yes Enter PGPLOT device XW hardcopy crab powerspec ps PS As a result the crab powerspec ps plot shown in Figure 22 was produced The 33 millisecond pulsation of the Crab is visible For the details on INTEGRAL absolute timing see Walter et al 2003 13 If your data have many short GTIs e g in the case of telemetry saturation due to a solar flare or when PICsIT is in non standard mode you can obtain spurious results A typical case is finding an 8sec period in your data due to the fact that the telemetry restart is synchronized with an 8 sec frame When possible compare your results with ii light that is immune of this problem and can reach about 0 1 sec binning 10 PICsIT data analysis Unfortunately PICsIT sensitivity is not high enough to create a good image for a single Science Window thus you should expect good results only if INTEGRAL is in staring mode and the source is really bright In the example below we use Crab observations done in staring mode Download and install as described in Section 6 1 the following Science Windows whose DOLs are assumed to be written to the file picsit lst scw 0039 003900020020 001 swg fits 1 scw 0039 003900020030 001 swg fits 1 scw 0039 003900020040 001 swg fits 1 scw 0039 003900020050 001 swg fits 1 scw 0039 003900020060 001 swg fits 1 Create the working directory picsit ima with the og creat
104. in standard mode for MULTIPLE Do not touch this parameter default 170 600 1000 IBIS IPS_E_band_max_m string List of higher energy boundary for PICsIT in standard mode for MULTIPLE Do not touch this parameter default 600 1000 10000 IBIS IP ChanNum integer Number of Energy bands for PICsIT in photon by photon mode possible values 1 300 Do not touch this parameter default 3 IBIS IP E band min s string List of lower energy boundary single Do not touch this parameter default keV 175 600 1000 ISDC IBIS Analysis User Manual Issue 5 1 100 IBIS IP E band max s string List of higher energy boundary single Do not touch this parameter default keV 600 1000 10000 IBIS IP E band min m string List of lower energy boundary multiple Do not touch this parameter default keV 350 600 1000 IBIS IP E band max m string List of higher energy boundary multiple Do not touch this parameter default keV 600 1000 13500 IBIS NoisyDetMethod integer Noisy Pixel detection method possible values O only normal noisy detection 1 add also spectral noisy detection default 0 These parameters are recommended by the IBIS team better not to change them IBIS min rise integer Minimum rise time default 7 IBIS max rise integer Maximum rise time default 90 IBIS_P_convFact real Conversion factor channel to energy default 7 0
105. in the images if the background subtraction is working correctly giving a better image before deciding what results to use and before applying it also to the spectral and lightcurve extraction levels Background subtraction can be tuned with the help of the SCW1_BKG_I_isgrBkgDol parameter If it is left empty then the background map is taken automatically from the IC files To have no background subtraction set SCW1_BKG_I_isgrBkgDol As a general guideline for short timescale e g 1 Science Window the background features should be less than the statistical uncertainties so that background removal is not expected to change the result by much On longer time scales mosaic image things can be different especially in the case of a Staring observation in which background features can accumulate and become important 8 2 4 Miscellanea on Imaging e With the parameter OBS1_ExtenType to find it on the GUI pages press the hidden button and go to the IMA page you can choose whether to keep the Residual and or the true Exposure image in the isgri_sky_ima fits file With the default 0 4 maps will be created per energy range Intensity Variance Significance and Residuals With OBS1 ExtenType 1 true exposure maps will be written instead of residual images at the 4 n extension of isgri sky ima fits OBS1_ExtenType 2 will add the true Exposure maps in an additional extension 0BS1 ExtenType 3 will add single true Exposure map
106. input background map is given then the background map fitting is performed Table 21 2i_spectra_extract parameters included into the main script Name Name Type Description in the main script executable SCW2_ISPE_idx_isgrResp idx_isgrResp string DOL of the index of ISGRI response matrices default SCW2_ISPE_DataMode DataMode integer Data Simulation mode possible values O real data 1 simulated data default 0 SCW2_ISPE_MethodInt MethodInt integer Method to be applied for the pixel value interpolation default 1 SCW2_ISPE_MethodFit MethodFit integer Method to be applied for background and source in tensity fitting possible values MethodFit 0 gt CHI2 MethodFit 1 gt Maximum Likelihood MethodFit 2 gt Least Squares MethodFit 6 gt iterative imaging like Least Squares fit default 6 SCW2 ISPE isgrUnifDol isgrUnifDol string DOL of the ISGRI detector uniformity default SCW2_ISPE_isgrBkgDol isgrBkgDol string DOL of the ISGRI background model default SCW2 ISPE tungAtt tungAtt string DOL of the Tungsten attenuation length fits file default SCW2 ISPE aluAtt aluAtt string DOL of the Aluminium attenuation length fits file default SCW2 ISPE leadAtt lead Att string DOL of the Lead attenuation length fits file default gt rebinned corrDol spe corrDol string DOL of the rebinned ISGRI off axis corrections for ec 22
107. ins The names of the possible analysis levels are given in section 5 Possible values COR COMP Also CLEAN value is possible default COR endLevel string Analysis level at which analysis finishes The names of the possible analysis levels are given in the section 5 possible values COR CLEAN We recommend you to proceed by steps as described in the cookbook default IMA2 staring boolean Enter yes if it was a staring observation It has an in fluence on PICsIT analysis for staring observation all shadowgrams are summed before the deconvolution default no tolerance real tolerance for staring In case of staring yes the check is performed that during the Science Windows within the Observation Group the spacecraft was sta ble within the given tolerance default 0 0001 sum spectra boolean Do the summing of spectra default no CAT refCat string DOL of Reference Catalog default 1S8DC REF CAT ISGRI FLAG 1 CAT_usrCat string DOL of User Catalog CURRENTLY IG NORED chatter integer Verbosity level possible values 0 5 0 errors only 1 warnings 2 normal default 2 IC_Group string DOL of Instrument Characteristics master group default REP BASE PROD idx ic ic master file fits 1 IC Alias string Selection alias for Instrument Characteristics default 0SA ISDC IBIS Analysis User Manual Issue 5 1 98 corrDol re
108. ion is equal to the product of the module count rate and the coding time The dead time due to the veto is equal to the product of the veto count rate and the veto time window etc The resulting dead time is taken as a sum of all the dead times connected with different effects Simple summing of dead times can be done since the estimations show that the coincidence probability between different types of events is low The values of the count rates is taken from the HK Data Structures IBIS DPE HRW and IBIS DPE CNV and the corresponding time windows are either measured instrumental or read into HK or IC all others VETO Compton 12 3 1 ibis isgr deadtime The executable ibis isgr deadtime calculates dead times resulting from count rates in ISGRI modules taking into account the instrument configuration ISGRI dead time is due to the combined effect of e Instrument count rate e Veto count rate from the lateral or lateral bottom according to IC file shielding e Calibration count rate e Compton coincidences if Compton mode is on Note that the problem of the VETO swapping on board is corrected almost every time through IC file IBIS VETO MOD VETO also sometimes has a wrong level this will be corrected in the future The 3 cases when it happened are in the IC file GNRL INTL BTI with the BTI TYPE ISGRI VETO LEVEL Table 10 ibis isgr deadtime parameters included into the main Script Name Name Type Description i
109. is User Manual Issue 5 1 84 table with total counts during integration time The axes of the grid are directed along the following axes AXIS 1 Channel number AXIS 2 Y position AXIS 3 Z position Spectral timing histograms are written to the Data Structure PICS SPTI RAW and contain the infor mation on the number of the events accumulated in the up to 8 energy bins during a given time amount see Table 30 Table 30 Content of PICS SPTI RAW Data Structure Column Name Description CELL 1 1st cell of the spectrum CELL 2 2nd cell of the spectrum CELL 3 3rd cell of the spectrum CELL_4 4th cell of the spectrum CELL 5 5th cell of the spectrum CELL 6 6th cell of the spectrum CELL 7 7th cell of the spectrum CELL_8 8th cell of the spectrum The local on board time and the channels definitions can be found in the PICS SPTI PRW Data Structure A 2 Prepared Data The main task of the Science Window Pipeline is to prepare raw data for the following Scientific Analysis It converts the housekeeping parameters into the physical units and makes some corrections and transfor mations of the raw data that are not included in Pre Processing The Summary of all the prepared Data Structures with scientific information can be found in Table 28 All these Data Structures has the only column OB_TIME with the on board time ISDC IBIS Analysis User Manual Issue 5 1 85 B Instrument Characteristics used in Data Analysis
110. is applied to the whole detector 1 parameter switches to this value automatically when background map is specified not an IC one 2 background is treated for each module separately default 0 Method to be applied for the pixel value interpolation possible values O dead zone pixels will be filled with 0 1 dead zone pixels will be filled with mean detector value 1 no dead zones default 1 0 gt no Noisy Pixel detection 1 gt use SE LECT FLAG method default 1 12 6 2 ip shadow ubc ip_shadow_ubc reads raw detector shadowgrams and performs the background correction Also detector dead zones are filled at this step Method to be applied for the pixel value interpolation in dead zones is defined by the parameter method int Expanded intensity and variance shadowgrams are produced as output Table 16 ip shadow ubc parameters included into the main script Name in the main script Name Type executable Description SCW1_BKG_P_method SCWI BKG P picsSUnifDOL picsSUnifDOL string SCW1_BKG P picsMUnifDOL picsMUnifDOL string SCWI BKG P picsSBBkgDOL picsSBkgDOL string SCW1_BKG_P_picsMBkgDOL picsMBkgDOL string method integer Method to use in scaling the background DOL of the PICsIT Detector Uniformity model single DOL of the PICsIT Detector Uniformity model multiple DOL of the PICsIT Detector Background model single DOL of the PICsIT Detecto
111. k for sources from a given catalog This catalog can be either the one provided by ISDC CAT_refCat ISDC_REF_CAT from which you can extract e g only the sources that have been detected by ISGRI ISDC_REF_CAT ISGRI_FLAG 1 or a catalog made on your own see section 9 6 to create a catalog on your own The number of sources that are detected in an image is important because detecting a source means also removing its ghosts from the images see section 7 1 The source search method is defined with the parameters OBS1_SearchMode and OBS1 ToSearch These parameters allow you the following possibilities e OBS1_SearchMode 0 This mode was developed for testing purposes and is not recommended for scientific use e OBS1_SearchMode 1 the software will look for all the sources of the input catalog that are in the field of view regardless of their detection level If the source gives a positive detection then the relevant results are saved in the isgri_sky_res fits file but see also discussion on OBS1_NegModels in Section 8 2 4 This mode can be useful in case your Science Window images are noisy and many fake new sources are detected Searching only the sources from a given catalog will avoid having ghost cleaning for fake sources 12Note that the run time is proportional to the number of sources detected ISDC IBIS Analysis User Manual Issue 5 1 35 e OBS1_SearchMode 2 The software will look for the K brightest sou
112. ll files with this data structure will be deleted dal detach og ibis fitsN 1 pattern ISGR SRCL RES delete y 9 2 Make your own Good Time Intervals Read this if you are interested to select photons arrived at a particular time period e g in analysis of flares or for phase resolved spectroscopy You should define Good Time Intervals GTIs with the help of the gti user program To create a GTI for IBIS starting on IJD 1322 68 and lasting 1 minute do not forget to convert it into days give the command 13 f any executable crashes then it terminates with non zero status The meaning of the status value can be found at http isdc unige ch index cgi Soft errors ISDC IBIS Analysis User Manual Issue 5 1 39 gti user gti user gti fits begin 1322 68 end length 6 944E 4 group og_ibis fits 1 unit day Then in the main page of the GUI Fig 12 you should set SCW1 GTI gtiUserI user gti fits 1 and specify the time format that was used in this file in the example above SCW1 GTI TimeFormat IJD More details on gti user are in the Data Analysis section of 1 9 3 Combining results from different observation groups Read this if you have a set of science windows belonging to different runs for which you have already built images spectra or lightcurves and want to combine the results Section 9 3 1 explains how to combine all the existing images in a final mosaic while Section 9 3 2 shows how to merge different light
113. lrow og_ibis fits 1 2 3 N Y rm isgri_mosa_ima fits rm isgri_mosa_res fits rm isgri_srcl_res fits e If you had previously run the spectral and lightcurve steps you have to detach the ISGRI SRCL RES data structure from all your Science Window groups swg ibis fits 1 That is to each Science Win dow scw group located in the REP_BASE_PROD obs dir directory you should do the following command cd REP BASE PROD obs dal detach object dir scw scw 001 swg_ibis fits 1 pattern ISGR SRCL RES delete n At this point you are ready to launch the analysis and to create a joint mosaic cd REP BASE PROD obs GROUP1 ibis science analysis ogDOL og ibis fits 1 startLevel CAT I endLevel IMA OBS1_DoPart2 2 See 8 2 2 for a description of the main parameters of the mosaic step The above command is valid in case you have just run the ScW analysis part so that you indeed keep the same energy boundaries Otherwise if you parameter file has changes in between you should add in the above the definition of IBIS II ChanNum IBIS II E band min and IBIS II E band max according to the boundaries of the single SCW maps you want to merge 9 3 2 Combining spectra and lightcurves from different observation groups In Sections 7 2 and 7 3 you have seen how to merge lightcurves and spectra from different Science Windows belonging to the same group In that case the file og ibis fits points to all the Science Windows and it is pos sible to launch t
114. ls see Figures 29 30 and 31 respectively 62 Overview of the binning background step for Imaging leen 63 Overview of the binning background step for Spectra a 63 Overview of the binning background step for Lightcurves len 63 IBIS Analysis User Manual Issue 5 1 viii 34 SP SF for the IBIS ISGRI telescope o occ coo cassadas inaona ea SS ww ISDC IBIS Analysis User Manual Issue 5 1 List of Tables 10 11 12 13 14 15 16 It 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 Beientihc Parameters of IBIS sss eeaeee a 3 Characteristics of the IBIS Telemetry Formats 000000004 eae 13 ibis_isgr_evts_tag parameters included into the main script o o 61 ibis_isgr_energy parameters included into the main script o o o 64 ip ev correction parameters included into the main script o 64 gti_create parameters included into the main script o o e ee eee 65 gti attitude parameters included into the main script lens 65 The gti_import parameters included into the main script sen 66 gti merge parameters included into the main script o o 66 ibis_isgr_deadtime parameters included into the main script 67 it_shadow_build parameters included into the main script 0 68 ip_ev_shadow_build parameters included into the
115. lt gt RA of the source for extracting PICsIT spectrum default DEC of the source for extracting PICsIT spectrum default gt DOL of the energy values for single events default gt DOL of the energy values for multiple events default gt Number of Channels possible values 0 300 default 51 List of lower limits of output energy bands single default List of upper limits of output energy bands single default List of lower limits of output energy bands multiple default gt List of upper limits of output energy bands multiple default gt Number of Channels possible values 0 300 default 51 List of lower limits of output energy bands for SINGLE default gt List of upper limits of output energy bands for SIN GLE default ISDC IBIS Analysis User Manual Issue 5 1 107 IBIS_SPS_E_band_min_m string List of lower limits of output energy bands for multiple default gt IBIS_SPS_E_band_max_m string List of upper limits of output energy bands for multiple default SCW2_ISPE_idx_isgrResp string DOL of the index of ISGRI response matrices default SCW2 ISPE _isgrarfDOL string DOL of the ARFs for XSPEC default SCW2_ISPE_DataMode integer Data Simulation mode default 0 SCW2_ISPE_MethodInt integer Method to be applied for the pixel value interpolation default 1 SCW2_ISPE_M
116. lysis http isdc unige ch Soft download osa osa_doc prod doc_tree html IBIS observer s manual http astro estec esa nl Integral AO2 AODocD IBIS v2 pdf ISGRI Scientific Validation Report http isdc unige ch Soft download osa osa_sw prod doc_tree html PICsIT Analysis Scientific Validation Report http isdc unige ch Soft download osa osa_sw prod doc_tree html ISDC OSA INST GUIDE Installation Guide for the INTEGRAL Off line Scientific Analysis http isdc unige ch Soft download osa osa_doc prod doc_tree html Di Cocco G Caroli E Celesti E et al 2003 A amp A 411 L189 A Goldwurm 1995 Exper Astron 6 9 A Goldwurm et al 2000 AIP 510 703 A Goldwurm et al 2001 Proc of 4th INTEGRAL Workshop ESA SP 459 p 497 Goldwurm A David P Foschini L et al 2003 A amp A 411 L223 S R Gottesman amp E F Fenimore 1989 Applied Optics 28 4344 G K Skinner R M Rideout 1995 Imaging in High Energy Astronomy 177 182 Walter R Favre P Dubath P et al 2003 A amp A 411 L25 ISDC IBIS Analysis User Manual Issue 5 1
117. meter of og create equal to OGID cd REP BASE PROD obs OGID cp cw 011800900010 001 isgri lcr fits isgri lcr 011800900010 bar fits barycent inCOL TIME outCOL TIME outD L isgri lcr 011800900010 bar fits 2 inDOL auxDOL aux adp 0118 001 orbit_historic fits 1 ra0BJ 255 9865 dec0BJ 37 84414 In the example we have applied barycentrisation to the first energy range of 4U 1700 377 that happens to be in the extension number 2 2 Thus the extension you give as outDOL depends on the source and energy range you need to correct The overview of the content of each extension is in the input file isgri_Icr fits 1 i e the first extension GROUPING Note that barycent tool does not use group concept and is used directly with the lightcurve But for it successful work the REF_BASE_PROD variable should be set and point to the place in which there is an ic directory e g directory_of_ic_files_installation__ ic See more details on barycent tool in the Data Analysis section of 1 9 9 Alternative Timing Analysis Read this if you are interested in extracting lightcurves on smaller time bins i e up to about 0 1 sec than the ones allowed by the standard tool 9 9 1 ii light The standard lightcurve extraction tool _lc_extract called within the general analysis script builds shad owgrams for each requested time and energy bin Thus this program is quite time consuming and it is not recommended to use i
118. mulae to a set of correlations computed by FFT The on axis System Point Spread Function SPSF on the whole FOV for an optimum system and PSF deconvolution is shown in Fig 32 Note the peak and flat level in the central FCFOV the secondary lobes coding noise in the PCFOV and the 8 main ghosts of the source peak in the PCFOV located at distances from the source which are a multiple of the basic pattern Figure 32 SPSF for the IBIS ISGRI telescope The average Point Source Location Error PSLE for an optimum coded aperture system with a defined SPSF depends on the source signal to noise ratio S N as following 1 PSLE R S N The IBIS ISGRI telescope assuming no error in pointing axis reconstruction or other systematic effects can locate a 30 o point like source at better than 1 Absolute error in attitude reconstruction for INTEGRAL is expected to be lt 20 In a standard analysis IBIS events or histograms are binned in detector images which are then corrected for detector and background non uniformity 7 and then processed by an iterative algorithm which decodes cleans and composes sky images For each detector image a sky image and its variance are obtained using the deconvolution procedure and then iteratively searched for sources and cleaned of the source side lobes In this iterative process the source peaks are fitted with the bi dimensional Gaussian and finely located ISDC IBIS Analysis User Manual
119. n in degrees DEC_OBJ Source declination in degrees Y_FIN Y axis fine position of the source in pixels Z FIN Z axis fine position of the source in pixels FIN_YZ_ERR Error of the fine position along the Y and Z axis in pixels RA_FIN Right Ascension of the fine position of the source DEC_FIN Declination of the fine position of the source FIN_RD_ERR Error of the fine position of the source in RA and DEC FLUX Flux values for a given energy band FLUX_ERR Flux errors for a given energy band DETSIG Source detection significance in ISGRI Table 51 Content of ISGR SKY RES IDX Data Structure Column Name Description TFIRST Time of the first data element TLAST Time of the last data element TELAPSE Total elapsed time of the data E_MIN Lower bound of the energy range E MAX Upper bound of the energy range Search for the sources in the FOV is then performed and a list of sources found is created Data Structure ISGR MOSA RES has the same structure as the ISGR SKY RES Table50 The index of lists of sources found in each map can be found in Data Structure ISGR MOS A RES IDX structure analogous ISDC IBIS Analysis User Manual Issue 5 1 93 to the one described in the Table 51 The output catalog containing the sources description is written to the data structure ISGR SRCL RES This Data Structure has structure similar to input catalog ISGR SRCL CAT Each row of this Data Structure contains the description of a source i
120. n the OG FOV If it was present in the input catalog all the input info is copied For each source found during the analysis the new info is added see Table 52 The DETSIG in ISGR SRCL RES is calculated from the results of the mosaic image and the results of the analysis at Science Window level detsig 4 Xdetsig where i is for all energy bands and all Science Windows and mosaic image For the FLUX and err_flux of ISGR SRCL RES you have lux flux N Zfluzxerr l fluxerr N where i for all Science Windows and a mosaic image for a given energy band Table 52 New information added to the ISGR SRCL RES Data Structure Column Name Description RA FIN Right Ascension of the fine position of the source DEC FIN Declination of the fine position of the source FIN_RD_ERR Error of the fine position of the source in RA and DEC SCW NUM number of times that the source was in SCW FOV If SCW NUM C 0 then it is a new source SCW NUM F number of times that the source was found in ScW image OG NUM number of times that the source was found in OG image With the help of stand alone program src collect it si possible to collect results from different science windows Results are written to the ISGR OBS RES Data Structure see Table 53 Table 53 Content of the ISGR OBS RES Data Structure Column Name Description SWID Science Window identifier SOURCE ID ISDC uniq
121. n the main script executable SCWI veto mod icDOL string DOL of the IC file for VETO model and width of Compton window default 12 3 2 ibis pics deadtime The executable ibis pics deadtime extracts from the housekeeping data the PICsIT intrinsic dead time of and dead time induced by the fortuitous coincidence with VETO and calibration system Contrary to the ISGRI case the dead time is measured by the on board electronics and we have only to decipher it from the telemetry data 12 4 ibis binning The main function of ibis binning is to split the data into energy and time bins The number of the time and energy bins depend on the purpose of the analysis The user can choose if the binning is done for imaging spectral extraction or light curve production Typically just one bin in time and few bins in energy are ISDC IBIS Analysis User Manual Issue 5 1 67 chosen for the image production one time bin and many energy bins for spectral extraction many time bins and just few energy bins for timing analysis This step is repeated for each Science Window in the observational group The shadowgram is created for each energy interval Script ibis binning combines the following executables e ii shadow build e ip ev shadow build e ip si shadow build 12 4 1 ii shadow build The executable ii_shadow_build creates shadowgrams of ISGRI events in the given time Tbin and energy Ebin ranges For every shad
122. nce By default the software will automatically take subtraction with one set of maps with about 1 7 Ms of integration time The default energy bands are in keV for single events 203 252 252 336 336 448 448 672 672 1036 1036 1848 1848 3584 3584 6720 For multiple events 336 448 448 672 672 1036 1036 1848 1848 3584 3584 6720 6720 9072 9072 13440 ISDC IBIS Analysis User Manual Issue 5 1 49 COR GTI DEAD BIN I BKG I CAT L IMA IMA2 BIN S SPE LCR COMP CLEAN isdc arc rev 2 cat hec gnrl refr cat 0020 fits 1 lSGRI FL amp G 1 Figure 23 Main page of the IBIS GUI This works for standard mode mode 41 only For photon by photon mode mode 43 the default values arel Number of Energy bands IBIS_IP_ChanNum 3 List of low energy boundaries keV single events IBIS_IP_E_band_min_s 175 600 1000 List of high energy boundaries keV single events IBIS_IP_E_band_max_s 600 1000 10000 List of low energy boundaries keV multiple events IBIS_IP_E_band_min_m 350 600 1000 List of high energy boundaries keV multiple events IBIS_IP_E_band_max_m 600 1000 13500 To select parameters specific for PICsIT analysis press the PICsIT button The PICsIT GUI page is shown in Figure 24 Depending on the observation mode staring or dithering there are two ways to analyze the PICsIT data The first by using the parameter staring yes can
123. nd idx directories are part of the OSA software distribution and should be installed following the Installation Guide for the INTEGRAL Data Analysis System 5 The actual data along with the auxiliary files scw and aux are sent to the Principal Investigators of the observation Alternatively the public data can be downloaded from the archive see Section 6 1 1 In case the data are already available on your system you can either copy these data to the relevant working directory or better create soft links as shown below Alternatively if you do not have any of the above data on your local system or if you do not have a local archive with the scw and the aux branch available follow the instructions in the next section to download data from the ISDC WWW site ln s directory of ic files installation ic ic ln s directory of ic files installation idx idx ln s directory of cat installation cat cat ln s directory of local archive scw scw ln s directory of local archive aux aux Then just create a file isgri gc lst containing the 5 lines scw 0051 005100410010 001 swg fits 1 scw 0051 005100420010 001 swg fits 1 ISDC IBIS Analysis User Manual Issue 5 1 18 scw 0051 005100430010 001 swg fits 1 scw 0051 005100440010 001 swg fits 1 scw 0051 005100450010 001 swg fits 1 and a file picsit Ist containing scw 0039 003900020020 001 swg fits 1 scw 0039 003900020030 001 swg fits 1 scw 0039 003900020040
124. ng to transparent elements and n_ to opaque ones for that given sky position This can be written T By Sy gt Cite ja WD Bij y Gir jy Wi Dr k kl where the decoding arrays are obtained from the mask M by Gt M and G 1 M then padded with 0 s outside mask region and where the sum is performed over all detector elements In the FCFOV we obtain the same result as the standard cross correlation To consider effects such as satellite drift corrections see 7 dead areas or other specific conditions a weighting array W is used to weigh properly the detector array before correlating it with the G arrays The balance array is el Gu j We Bij el Guy j Wki ISDC IBIS Analysis User Manual Issue 5 1 73 The variance which is not constant outside the FCFOV is computed accordingly Vig Y Du Gt saw T Bj Y Dri Gr Wii since the cross terms G G vanish Note however that when the weights W refer to the same pixel in D the terms G W must be summed before squaring see 7 The varying effective area can be calculated by a similar formula and used to renormalize after background subtraction to FCFOV count rates All this can be performed for sampling finer than 1 pixel per mask element and using a G array convolved with detector the PSF in order to optimize S N for point sources with corresponding normalizations This procedure can be carried out with a fast algorithm by reducing previous for
125. odule 3 IP DEADTIME 4 Dead time for Semi module 4 IP DEADTIME S5 Dead time for Semi module 5 IP DEADTIME 6 Dead time for Semi module 6 IP DEADTIME 7 Dead time for Semi module 7 IP DEADTIME 0 Dead time for Semi module 8 IP DEADTIME 1 Dead time for Semi module 9 IP DEADTIME 2 Dead time for Semi module 10 IP DEADTIME 3 Dead time for Semi module 11 IP DEADTIME 4 Dead time for Semi module 12 IP DEADTIME 5 Dead time for Semi module 13 IP DEADTIME 6 Dead time for Semi module 14 IP DEADTIME 7 Dead time for Semi module 15 Table 45 Content of COMP DEAD SCP Doata Structures Column Name Description OB TIME On board time IC DEADTIME O0 Dead time for module 0 IC DEADTIME 1 Dead time for module 1 IC DEADTIME 2 Dead time for module 2 IC DEADTIME 3 Dead time for module 3 IC_DEADTIME 4 Dead time for module 4 IC DEADTIME 5 Dead time for module 5 IC DEADTIME 6 Dead time for module 6 IC DEADTIME 7 Dead time for module 7 ISDC IBIS Analysis User Manual Issue 5 1 90 C 4 ibis_binning This script prepares IBIS data for scientific analysis Its main function is to split the data into energy bins and time bins For each time and energy ranges detector shadowgram and a corresponding efficiency shadowgram are created Output Data Structures are listed in the Table 46 These Data Structures keep the position of each pixel and the total counts in given energy band du
126. ogram as described in Section 9 10 Once you have run the script until the SPE level included you are ready to launch the stand alone lightcurve extraction tool ii light works on the Science Window level only meaning that you have to launch it once per Science Window It does not change the structure of the Science Window group so if you would like to compare the results of i light and i lc extract it is worth to run the analysis until SPE use i light as shown below then go back to REP BASE PROD obs OGID and relaunch the analysis from LCR to LCR in the standard way The output lightcurve files of the standard software are automatically called isgri lcr fits Alternatively if you have first run the standard lightcurve extraction i e the LCR level you can still run ii light following the instructions below We give an example of the shell script that launches i light for all Science Windows of your group OGID from a particular revolution 0051 in example below cd REP BASE PROD obs OGID Setenv run 0051 foreach file scw run swg ibis fits echo file ii light inSwg file num e 4 e min 20 40 60 100 e max 40 60 100 200 delta t 10 outLC file h lcr fits ISGR SRC LCR IDX tpl GTIname MERGED_ISGRI corrDol rebinned corr ima fits context scw run rev 001 idx isgri context index fits 1 backDol rebinned back ima fits tee out log end As a result of this script you will have in eac
127. olution in every Science Window and the output files are under scw RRRRPPPPSSSF 001 picsit ima fits Scw RRRRPPPPSSSF 001 picsit sky res fits and the integration of all these images mosaic is in picsit ima fits 10 2 PICsIT spectral extraction from the mosaic image It is also possible produce the source spectrum from the mosaic image ISDC IBIS Analysis User Manual Issue 5 1 52 Figure 25 Crab significance image in the 252 336 keV energy band as seen by PICsIT At http isdc unige ch index cgi Soft scripts you find an example of such a of perl script spextract_pics pl To use it create the picsit_default_bins txt file with the grouping of channels corresponding to the energy boundaries of the images we have 0 4 5 5 11 7 12 24 13 25 40 16 41 714 34 75 128 54 129 250 122 251 509 259 510 977 468 978 1023 46 and then rebin the response matrix with the rbnrmf from the FTOOLS package rbnrmf infile REP_BASE_PROD ic ibis rsp pics_srmf_grp_0002 fits outfile pics rmf fits binfile picsit_default_bins txt Create also a list of files you want to use for spectral extraction In the case of staring file picsit 1st will contain a single line picsit_ima fits Now you are ready to extract the spectrum To do this you can either fill the values manually from the picsit_sky_res file or extract the fluxes from the brightest pixel around the catalog position with the help of the spextract_pics pl
128. on is deciphered and rewritten into the set of FITS files RAW data Then the local on board time is converted into the common on board time OBT and the House Keeping HK parameters into physical units PRP data These steps are done at ISDC and you do not have to redo them In the Appendix you will find the description of the raw and prepared data and also the description of the instrument characteristic files that are used in the Scientific Analysis INTEGRAL data is organized into the so called Science Windows see Introduction to the INTEGRAL Data Analysis 1 for more explanations During the scientific analysis all the Science Windows belonging to the same observation are grouped together to form the Observation Group Figure 10 shows in details the different steps performed by the scientific analysis script ibis_science_analysis This high level script consists of three smaller ones ibis_scw1_analysis ibis_obs1_analysis and ibis_scw2_analysis ibis_scw1_analysis and ibis_scw2_analysis work on a Science Window basis while ibis_obs1_analysis works on the Observation Group basis Each subscript performs the tasks shown in Figure 10 explained in more details in the text below ibis science analysis ibis scw1 analysis a i aa aa aaa aL i u 1 Data Correction i COR ibis_correction 1 Corrected data i 1 I n a 1 Good Time Handling f GTI ibis_gti t Good Time Intervals f 1 Dead Time Calculation DEAD ibis_dead
129. ones of the detectors in accordance with the chosen method creating the extended intensity map Iex Then with the help of the IC background B and uniformity U maps See Section B 4 a corrected intensity map Ieor is produced Iex B kor U Script bis_background_cor combines the following executables e ii_shadow_ubc e ip_shadow_ubc 12 6 1 2i_shadow_ubc it_shadow_ubc reads all raw detector and corresponding efficiency shadowgrams and fills the detector dead zones it_shadow_ubc is run in three cases to produce images spectra and lightcurves In the imaging case for each pair of detector efficiency shadowgrams it performs the background correction for the uniform ISDC IBIS Analysis User Manual Issue 5 1 70 default and non uniform spatial distribution As output it produces 3 shadowgrams of larger dimensions corrected expanded shadowgram and corresponding variance and efficiency shadowgrams Method to be applied for the pixel value interpolation in dead zones is defined by the parameter method int Table 15 it_shadow_ubc parameters included into the main script Name in the main script Name Type executable Description ii shadow ubc SCWI1 BKG I method cor SCWI1 BKG I method int IBIS_NoisyDetMethod method_cor string method_int string NoisyPixControl integer Method to be applied for background removal possible values 0 2 0 background from IC tree
130. ons default gt DOL of the background maps default Time bin in seconds possible values 0 1 10000 default 100 Number of energy channels possible values 1 10 default 2 List of low energy boundaries default 15 40 List of high energy boundaries default 40 300 ISDC IBIS Analysis User Manual Issue 5 1 83 A Low Level Processing Data Products A 1 Raw Data Table 28 summarizes all Data Structures with the raw events measured by IBIS The description of these Data Structures can be found below Table 28 List of IBIS _ _RAW Data Structures Observing Type of event Raw Prepared Corrected mode Data Structure Data Structure Data Structure Photon ISGRI I ISGR EVTS RAW ISGR EVTS PRP ISGR EVTS COR PICsIT single PS PICS SGLE RAW PICS SGLE PRP PICS SGLE COR by PICsIT multiple PM PICS MULE RAW PICS MULE PRP PICS MULE COR Compton single CS COMP SGLE RAW COMP SGLE PRP COMP SGLE COR photon Compton multiple CM COMP MULE RAW COMP MULE PRP COMP MULE COR Spectral Imaging PICsIT single PICS SISH RAW PICS SISH PRP PICS SISH COR Histogram PICsIT multiple PICS SIMH RAW PICS SIMH PRP Spectral Timing PICS SPTI RAW PICS SPTI PRP Histogram A 1 1 Photon by photon mode In this mode Data Structures with similar contents are created for all types of events Data Structures with names finished by RAW contain the information
131. owgram a corresponding efficiency shadowgram is created For pixels active during the revolution switch status ON efficiency falls into two components and is null for the others the first factor takes into account the dead time D of the corresponding module MDU the second factor reflects the efficiency energy dependence LT for the lower energy bins due to the low threshold operation limit such that Eff Tbin Ebin y z 1 D Tbin mdu LT Ebin y z It is this value that is given in the shadowgram efficiency maps This executable also applies two different noisy pixel detection techniques The first one is time based it discriminates every pixel for which the scientific SELECT FLAG equals one even only once over all the Science Window events Note this flag was filled by the executable ibis isgr evts flag The second method is spectral based it discriminates pixels by estimating their spectral deviation from the average ISGRI spectrum This spectral method can be switched ON OFF by parameter NoisyDetFlag Table 11 ii shadow bwild parameters included into the main script Name Name Type Description in the main script executable IBIS II ChanNum isgri e num integer Number of energy intervals for ISGRI possible values 1 10 default 7 IBIS IL E band min isgri e min string List of lower energy boundaries keV default 15 40 100 200 400 700 1200 IBIS IL E band max isgri e max string List of upper energy bounda
132. pe and call ibis science analysis cd obs picsit ima ibis science analysis After a few seconds the main page of the IBIS Graphical User Interface GUI appears as shown in Figure 29 ISDC IBIS Analysis User Manual Issue 5 1 54 Change start startLevel BIN_S and end endLevel SPE levels Disable ISGRI analysis by the checking SWITCH _disablelsgri button and enable PICsIT by unchecking the SWITCH disablePICSIT button To select parameters specific for the PICsIT analysis press the PICsIT button PICsIT GUI page is shown in Figure 24 Set the name of the source and its coordinates note that below we give the syntax for the command line case while in the GUI there should be no quotes PICsIT_source_name Crab PICsIT_source_ra 83 63 PICsIT_source_dec 22 01 Click on Ok and return to the main GUI window Press Run 10 3 1 Displaying the results of PICsIT spectral analysis The output spectra are created for each science window even in staring mode They are located at scw 0039000200X0 001 picsit spec fits To sum them up you can use mathpha FTOOL Below an example of ac shell script to sum up the spectra is given cd REP_BASE_PROD obs picsit_spe scw mkdir pha foreach dir 001 set fn echo dir cut c 1 12 set fb echo fn pha fextract dir picsit_spec fits 2 pha fb end cd pha mv 003900020020 pha sum pha set npha 1 foreach pha 0 pha npha mathpha units R errmeth gaus expr sum p
133. photon is derived in each crystal bar from the intensity of the flash recorded in the photodiode The energy resolution of PICsIT is a function of the signal to noise of the event which in turn is governed by factors operating conditions and PIN capacity e PICsIT multiple event Several PICsIT detection units in one submodule were excited during one event generating several scintillation flashes The energy of the primary photon is determined from the sum of the energies of all detected events The position of the incoming photon is attributed to the position of the most energetic event ISDC IBIS Analysis User Manual Issue 5 1 11 e Compton single event Photons arriving in either ISGRI or PICsIT produce secondary photon via Compton scattering detected in another layer The position of the incoming photon is attributed to the position of the most energetic event and the energy is determined as the sum of the detected events energies e Compton multiple event One ISGRI detection unit and several PICsIT detection units in one submodule were excited As in previous cases the position of the incoming photon is attributed to the position of the most energetic event and the energy is determined as the sum of the detected events energies In Fig 9 the efficiencies of the various detection techniques is shown evaluated by Monte Carlo simulation BIS ISGRI A rn 0 100 Pica single arg RG For ES
134. public data up to April 2005 ISGRI data alone will be processed SWITCH_disablePICsIT yes through all the available levels shown in GENERAL levelList within COR and IMA2 No additional good time interval will be applied to the data SCW1_GTI gtiUserl field is empty which also implies that the last parameter SCW1_GTI_TimeFormat is not effective You are ready to set the parameters specific for imaging Press the ISGRI_IMA button at the bottom of the GUI Another box shown in Figure 13 appears With the parameters displayed in the GUI you will create 4 different images of the sky corresponding to 4 energy bands IBIS 11 ChanNum 4 in the ranges 20 40 40 60 60 100 and 100 200 keV You will let the software look for the 15 brightest sources in the field of view OBS1_Searchmode 2 and OBS1_ToSearch 15 with detection significance higher than 6 for catalog sources OBS1_MinCatSouSnr 6 and 7 for new sources OBS1_MinNewSouSnr 7 Given that you are analysing the crowded Galactic center it might be better to increase the number of sources you are looking for Change manually OBS1_ToSearch to 25 The position of all the catalog sources will be fitted OBS1 SouFit 0 Resulting images will be cleaned with the available background maps provided by the IBIS team empty value of SCW1 BKG LisgrBkgDol means usage of the default map REP BASE PROD ic ibis bkg isgr back bkg 0005 fits After creation of all the individual science window images the mosaic imag
135. r Background model multiple maps possible values 0 model in cts is normalized by the time of observation 1 model in cts is normalized by the mean count value default 0 ISDC IBIS Analysis User Manual Issue 5 1 71 12 7 Catalogs The catalog extraction selects the sources in the field of view FOV from the references catalog 12 7 1 cat extract The executable cat extract performs the source selection from a reference catalog The reference catalog should have the same structure as GNRL REFR CAT see Table 48 in Appendix C 5 Its DOL is passed in the parameter refCat There is no standard output catalogue for IBIS and the parameter outExt must be filled Table 17 cat_extract parameters included into the main script Name Name Type Description in the main script executable CAT refCat ref cat string DOL of the reference catalogue default value ISDC_REF_CAT OBS1_CAT radiusMin radiusMin string Low limit for the position selection default 0 OBS1_CAT radiusMax radiusMax string High limit for the position selection default 20 OBS1_CAT fluxDef fluxDef string Column used for flux selection default OBS1_CAT fluxMin fluxMin string Low limit for flux selection in ph cm s default OBS1_CAT fluxMax fluxMax string High limit for flux selection in ph cm s default OBS1_CAT class class string Select
136. rUnifDol string DOL of the ISGRI detector uniformity possible values DOL for a specific model no uniformity correction gt gt DOL is taken from the IC tree default SCW1_BKG LisgrBkgDol string DOL of the ISGRI background model possible values DOL for a specific model no background subtraction DOL is taken from the IC tree default gt SCW1_BKG 1 method cor string Method to be applied for background removal default 0 SCW1_BKG_I_method_int string Method to be applied for the pixel value interpolation default 1 SCW1 BKG P method integer Method applied in filling gaps possible values 0 model in cts is normalized by the time of obser vation 1 model in cts is normalized by the mean count value default 0 SCWI1 BKG picsSUnifDOL string DOL of the PICsIT Detector Uniformity model sin gle default SCW1_BKG_picsSBkgDOL string DOL of the PICsIT Detector Background model sin gle default gt SCW1_BKG picsMUnifDOL string DOL of the PICsIT Detector Uniformity model mul tiple default ISDC IBIS Analysis User Manual Issue 5 1 103 SCW1_BKG_picsMBkgDOL string DOL of the PICsIT Detector Background model mul tiple default gt Parameters specific to OBSI pipeline ii sk yimage parameters OBS1_DataMode rebin_slope rebin_arfDol OBS1_SearchMode OBS
137. rces in the field where K OBS1_ToSearch They can be either known sources more significant than OBS1_MinCatSouSnr or new sources more significant than OBS1_MinNewSouSnr This mode is useful if you are interested in having a first glance at your field if you are interested in bright sources only or if you run your analysis on large data sets In fact in these cases you would not like to spend most of your time collecting information on weak sources that are not detected in a single Science Window The drawback of this method is that these undetected weak sources can produce ghosts in the mosaic image We recommend you to start the analysis with OBS1_SearchMode 2 with a high OBS1 ToSearch value around 20 especially for the Galactic plane or Centre crowded regions see the sources that are detected and prepare your own catalog of detected sources see section 9 6 Then launch again the analysis with OBS1_SearchMode 3 described below and give your catalog as input for the analysis CAT_refCat usrcat fits 1 e OBS1_SearchMode 3 The software will look for all the catalog sources regardless of their detection level plus for K significant excesses more significant than OBS1 MinNewSouSnr where K OBS1 ToSearch All these sources will be saved in the final isgri sky res fits file if their detection significance is positive but see also discussion on OBS1 NegModels in Section 8 2 4 This mode is very efficient in cleaning
138. reated during the spectral step that we have just run This means that at this stage you can extract the lightcurve only of the sources for which a spectrum has been created already So leave SCW2 cat for extract to point to specat fits By default for each source from the input catalog specat fits in our example four lightcurves in 20 40 40 60 60 100 and 100 200 keV energy bands with 100 sec time bins will be created The lightcurve extraction is performed by building shadowgrams for each time and energy bin Hence this step is time and space consuming Note that due to CFITSIO limitations the product of number of energy bins by number of time bins in a science window should be less than 250 Press Ok the window will disappear and you are back to the main GUI page Press Save and then Run 9 To read a given extension in XSPEC you have to specify it in curly brackets data pha fits 3 10PIF is a number between 0 and 1 which expresses the theoretical degree of illumination of each detector pixel for a given source in the sky ISDC IBIS Analysis User Manual Issue 5 1 32 7 3 1 Results of the Lightcurve Extraction Lightcurves are produced for each science window scw 0051004X0010 001 isgri_lcr fits X 1 5 To create a merged lightcurve in the 20 40 keV energy range i e to store in one file all the available lightcurves of a given source use lc pick lc pick source 4U 1700 377 attach n group
139. ribing the desired binning of the response matrix By default set with empty line the latest available file with the rebinned response matrix is used Currently it is REP BASE PROD ic ibis rsp isgr rmf grp 0017 fits 3 with 16 channels in it See sections 8 3 and 9 4 if you want to define your own spectral binning Background maps With the SCW2_BKG_I_isgrBkgDol parameter you can specify the background map to be used in the spectral and timing analysis It is recommended to use the same background map as in the imaging case De fault empty value corresponds to the default map REP_BASE_PROD ic ibis bkg isgr_back_bkg_0005 fits Input catalog for Spectral and Lightcurve extraction By default a spectrum will be created for all sources listed in the isgri_srcl_res fits catalog created during the IMA step The position of the source will be taken from RA_FIN DEC_FIN columns Note however that spectral extraction is time consuming and it is not recommended to include sources that are faint in comparison with the source of interest It is not recommended to have more than 30 sources in the input catalog as the software might crash otherwise Copy isgri_srcl_res fits to another file say specat fits as shown below leaving only sources with significance higher than 6 cd REP_BASE_PROD obs isgri_gc fcopy isgri_srcl_res fits ISGR SRCL RES DETSIG gt 6 0 specat fits Note that there should be spaces around gt As we h
140. ries keV default 40 100 200 400 700 1200 2500 IBIS min rise isgri min rise integer Minimum rise time default 7 IBIS max rise isgri max rise integer Maximum rise time default 80 IBIS NoisyDetMethod NoisyDetFlag integer Defines the way to deal with noisy pixels possible values 0 Time based noisy detection 1 Time based 4 Spectral based method default 1 12 4 2 ip ev shadow build ip ev shadow build takes as an input PICsIT data received in photon by photon mode For each given energy and time range intensity and efficiency shadowgrams are produced Efficiency is defined as Eff 1 D x Ton T ISDC IBIS Analysis User Manual Issue 5 1 68 where Ton T is given by the GTI and the total observation length Table 12 ip_ev_shadow_build parameters included into the main script Name Name Type Description in the main script executable SCW1_BIN clean Trk cleanTrk integer Cleaning of cosmic ray induced events SCW2_BIN_cleanTrk possible values 0 No 1 Yes default 1 IBIS_IP_ChanNum picsit_e_bin integer Number of Energy bands default 3 IBIS_IP_E_band_min s picsit_e_min _s string List of lower energy boundaries for PICsIT single events default 175 600 1000 IBIS_IP_E_band_max _s picsit e max s string List of higher energy boundaries for PICsIT single events default 600 1000 10000 IBIS_IP_E_band_min s picsit emin_m string Lis
141. ries specified in the second parameter 9 5 Some tricks on saving disk space and CPU time To gain time and space it is possible to create the rebinned correction and background maps rebinned fits only once and then give them as an input for the rest ISDC IBIS Analysis User Manual Issue 5 1 43 Analyse one science window from COR to SPE copy the maps somewhere and make them read only Then launch the analysis for other science windows specifying the following parameters in your ibis_science_analysis call rebinned_corrDol_ima your_path rebinned_corr_ima fits 1 rebinned_corrDol_spe your_path rebinned_corr_spe fits 1 rebinned_backDol_ima your_path rebinned_back_ima fits 1 rebinned_backDol_spe your_path rebinned_back_spe fits 1 IMPORTANT rebinned maps are created for a given set of energies only so these have to be kept the same 9 6 Create your own catalog Read this if you are familiar with the sources in your field of view and you want to build your own catalog for the Imaging step As already discussed in Section 8 2 1 during the imaging step IMA it can be very useful to use your own input catalog The easiest way to build it is to modify the general catalog with the help of the fcopy program of FTOOLS For example if you want to create a catalog usrcat fits with only three sources Crab 3C111 and XPer do the following cd REP_BASE_PROD fcopy ISDC_REF_CAT NAME Crab NAME 3C 111 NAME
142. ring integration time or efficiency correspondingly The boundaries of the energy and time bins can be found in the corresponding index Data Structures see Table 47 for details the abbreviations used in this table were introduced in Table 46 C 4 1 ii shadow bwild ii shadow build prepares ISGRI data for scientific analysis During the run of this executable Data Structures ISGR DETE SHD for a detector shadowgrams and ISGR EFFI SHD for ISGRI detector efficiency shadowgrams are filled These Data Structures keep the position of each pixel and the total counts in given energy band during integration time or efficiency corre spondingly During PICSIT analysis the same information about the PICSIT detector is written to PICS DETE SHD and PICS EFFI SHD Data Structures Table 46 List of Data Structures produced at BIN level Instrument Type of shadowgram Output Data Structure ISGRI detector ID ISGR DETE SHD efficiency IE ISGR EFFI SHD PICsIT detector PD PICS DETE SHD efficiency PE PICS EFFI SHD Table 47 Content of _ _SHD IDX Data Structures Column Name Description Shadowgram Type ISDCLEVL ISDC level of data processing ID IE PD PE TFIRST Time of the first data element ID IE PD PE TLAST Time of the last data element ID IE PD PE TELAPSE Total elapsed time of the data ID IE PD PE CHANMIN Lowest channel of the energy range ID IE CHANMAX Highest channel of the energy range ID IE
143. rray for multiple events ISDC IBIS Analysis User Manual Issue 5 1 87 COMP SBAC BKG COMP SUNI BKG COMP MBAC BKG COMP MUNI BKG COMPTON instrument background array for single events COMPTON instrument background uniformity array for single events COMPTON instrument background array for multiple events COMPTON instrument background uniformity array for multiple events For each type of Data Structures in Table 37 there is an Index Its content is given in Table 38 Two last columns RISE_MIN and RISE_MAX are present only in ISGR BACK BKG IDX and ISGR UNIF BKG IDX Indexes Table 38 Content of Indexes for Table 37 Data Structures Column Name Description VERSION VSTART VSTOP E_MIN E MAX EXPOSURE VETO_THR METH_BKG RISE_MIN RISE MAX Version of the instrument characteristic file Start of validity time in IJD End of validity time in IJD Lower bound of the energy range Upper bound of the energy range Effective exposure time Veto threshold Method used to produce this background image Minimum event rise time channel 0 127 Maximum event rise time channel 0 127 ISDC IBIS Analysis User Manual Issue 5 1 88 C Science Data Products C 1 ibis correction This script converts photons energy into keV with the help of the calibration data Table 39 summarises the output Data Structures Table 39 List of Data Structures produced at COR level Observing mode Typ
144. rrors of the reconstructed peaks Since V G x D XD the variance associated with each reconstructed sky image pixel is constant in the FCFOV and equal to the total counts recorded by the detector therefore the source signal to noise is simply 29 Cg N JVCs Cp where Cs and Cp are source and background counts These masks also have nearly equal number of trans parent and opaque elements and therefore offer minimum statistical error in condition of high background typical for the y ray domain However the sensitivity also depends on the detector spatial resolution and an imaging efficiency factor must be applied to this maximum S N to account for this effect Discrete cross correlation to compute sky and variance images can be written Sij gt GirjmDa Vij gt gt Ging Du kl kl where Poisson statistics was assumed This standard deconvolution in FCFOV can be extended in the PCFOV by extending the correlation of the decoding array G with the detector array D in a non cyclic form padding G with 0 elements Since only the detector section modulated by the PC source is used to reconstruct the signal the statistical error at the source position and significance of the ghost peaks are minimized However to ensure a flat image in the absence of sources detector pixels which for a given sky position correspond to opaque mask elements must be balanced before subtraction with the factor b n n where n is the number of pixels correspondi
145. rticular pixel countrate is too high relatively to the module countrate then the on board electronics switch it off In ISGRI case the noisy pixels can recover after being switched off for some time and disabled pixels are periodically reset to check their status In PICsIT case pixels cannot be recovered that easily PICsIT pixel will remain off once killed Only if half of the detector or so will be off an attempt will be made to turn pixels on The current situation is shown on Figure 8 Overall the killed pixels are less than 1 3 2 4 On board Calibration Unit IBIS contains an on board collimated radioactive Na source This allows regular calibration of PICsIT at both the 511 keV line calibration to better than 196 in 4 hours and 1275 keV 196 in 8 hours ISGRI can also use the 511 keV line albeit at lower efficiency Any energy deposits from untagged photons will have an impact of 196 on the overall continuum sensitivity between 100 keV and 2 MeV 3 2 5 Veto Shield The Veto shield is crucial to the operation of IBIS IBIS uses anticoincidence logic to accept or reject detected events as real photons in the field of view or background particles or photons propagating through ISDC IBIS Analysis User Manual Issue 5 1 9 SM2 SMI SMI SM2 EIU F 08 a 8 7 4 Y Fi 8 Tr The schematic view of PICsIT layer Each module number is indicated The dotted lines represents the division in semimodules whose
146. s Example assuming Nim Nsp 30 shadowgrams already created for images and spectra for a Tscw 3000 s science window duration 4 light curves in Ne 4 energy bands can be created for a total of Nlci 9942 Nim Nsp 9912 light curve images with the minimum time bin Tbin given by Tbin Ne x Tscw Nlci 4 x 3000 9912 1 2 s ISDC IBIS Analysis User Manual Issue 5 1 58 8 Version 12 of XSPEC cannot read the ISGRI spectra extracted per ScW in isgri spectrum fits beyond the first extension In case you want to study the ScW by ScW spectra of a given source you may either use XSPEC 11 or use spe_pick to extract the spectra in PHA2 format single y option which can be read by XSPEC 12 9 ii pif crashes if the input catalog inCat contains more than 500 sources 11 2 PICsIT 1 An improvement in the PICsIT spectrum extraction executable with the PIF method has been imple mented in the OSA 5 1 Despite the improvement under certain conditions e g staring observations the algorithm is still unstable We still suggest the user to continue adopting the spectra extraction from images as explained in OSA4 2 A RMF already rebinned for the channels of the imaging pipeline is available in the IC files ISDC IBIS Analysis User Manual Issue 5 1 59 Part III Data Analysis in Details ISDC IBIS Analysis User Manual Issue 5 1 60 12 Science Analysis In the Cookbook you have seen that in order to run the Scientific Analy
147. s PICSIT 0 976 500ms selected from ground ISDC IBIS Analysis User Manual Issue 5 1 3 1000 IThK eT ry ed pS US ES e jen AE INGA d MIC GT A Ln s D XCSIT multiple 100 gt a 10 10 100 1000 10000 energy keV Figure 1 IBIS effective area 3 Instrument Description 3 1 The Overall Design IBIS is gamma ray imager operating in the energy range 20 keV to 10 MeV with two simultaneously operating detectors covering the full energy range located behind a Tungsten mask which provides the encoding The coded mask is optimized for high angular resolution As diffraction is negligible at gamma ray wave lengths the angular resolution of a coded mask telescope is limited by the spatial resolution of the detector array The angular resolution of a coded mask telescope d0 is defined by the ratio between the mask element size C 11 2 mm and the mask to detection plane distance H 3133 mm C 1 d arctan 5 12 IBIS is made of a large number of small fully independent pixels The detector features two layers ISGRI and PICsIT the first is made of Cadmium Telluride CdTe solid state detectors and the second of Caesium Iodide CsI scintillator crystals This configuration ensures a good broad line and continuum sensitivity over the wide spectral range covered by IBIS The double layer discrete element design of IBIS allows the paths of interacting photons to be tracked in 3D i
148. s green boxes As you can see there are three sources labelled as NEW This example ISDC IBIS Analysis User Manual Issue 5 1 26 isgri_sky_ima 1 Index isgri_sky_ima 2 st Intensity 1 Energy Band isgri sky ima 3 st Variance 1 Energy Band isgri sky ima 4 T sc smi E isgri sky ima 5 at Residuals 1 Energy Band isgri sky ima 6 Lntensity 2 Energy Band Figure 15 Sketch of the isgri sky ima fits structure left and extract from the Index table right shows that you should be careful with the new sources found by the software and always make a detailed analysis to verify whether they are real or spurious ones In a coded mask instrument a true point source will cause secondary lobes 8 main ghosts aligned with the detector edges at a distance that is a multiple of the mask basic pattern 10 7 degrees in IBIS ISGRI case If the source is detected its ghosts will be cleaned and will not be included in the mosaic However if a source is too weak to be automatically detected in a single Science Window its ghosts are not cleaned they can appear in the mosaic image and even be found by the software as new sources In the present case three sources were recognized by the software as new ones These three sources NEW 1 NEW_2 and NEW 3 are the ghosts of 4U 1722 30 There is an easy way to collect from different science windows all the information related to a given source and energy band In the example belo
149. s the background while the slope gives the flux of the source in one fully illuminated pixel Normalization is a number of counts in a perfect detector if source is on axis half of all detector pixels illuminated Care has been taken so that structure is compatible with HEASARC tools There are no limits on the size of time bin up to 0 1s and number of energy bands ii light is not the official lightcurve extraction tool and should be used mainly to check relative variability of bright sources within a given Science Window rather than for a long term absolute flux estimate Table 27 i light parameters Name Type Description inSwg string DOL of the input Observation Group default gt outSwg string DOL of the output Observation Group default gt outLC string Dol of the light curves file default ISDC IBIS Analysis User Manual Issue 5 1 82 context GTIname select pifDOL deadDOL corrDol backDol delta_t num_e emin e max string string string string string string string real integer string string DOL of the context where we can find low threshold default gt Name of the GTI to be applied default Event selection condition default gt Dol of the PIF or of the index of PIF default gt Dol of the ISGR DEAD SCP default gt DOL of the isgri off axis correcti
150. s are written to the PICS SKY RES C 8 Spectral Analysis C 8 1 w _spectra_extract ii spectra extract reads the shadowgram for each input energy band and creates a spectrum for background and each source from isgri_srcl_res fits file The result is written to the ISGR EVTS SPE and ISGR EVTS SPE IDX Data Structures Table 54 Content of the ISGR EVTS SPE Data Structure Column Name Description CHANNEL Channel number RATE Countrate in the given channel SYS_ERR Systematic error STAT_ERR Statistical error QUALITY Quality flag GROUPING Grouping flag Table 55 Content of the ISGR EVTS SPE IDX Data Struc ture Column Name Description SOURCEID ISDC unique source identifier RA_OBJ Source right ascension in degrees DEC_OBJ Source declination in degrees TFIRST Time of the first data element TLAST Time of the last data element TELAPSE Total elapsed time of the data ISDC IBIS Analysis User Manual Issue 5 1 95 C 9 Timing Analysis C 9 1 ip st lc extract This program build light curves and related errors starting from spectral timing data of PICsIT The content of the filled Data Structures is given in the Tables 56 57 Table 56 Content of the PICS EVTS LCR IDX Data Struc ture Column Name Description SOURCEID ISDC unique source identifier CHANMIN Lowest channel of the energy range CHANMAX Highest channel of the energy range E MIN Lower bound of the energy ran
151. s binning 3 og ibis ii shadow build vg ite 2 w pixel status ip shadow build ev si 3 EFFLIC file 1 De o 2 BEG IC file ii map rebin rebinned maps ge ibis background cor E og ibis ii shadow ubc 2 Z background modell iP shadow ubc ogibis y a a Figure 29 Overview of the binning background step for Imaging Binning backgroud step for SPE ibis binning i og ibis ii shadow build ss lh 3 pixel status jp dd i evsi P ip shadow build ev si EFFLIC file 7 bi binid e De BKG IC file ii map rebin rebinned maps ibis background cor dis ii shadow ubc s i og ibis ip shadow ubc og ibis 2 e Figure 30 Overview of the binning background step for Spectra Binning backgroud step for Timing ibis binning E og ibis ii shadow build og Mis E pixel status ip shadow build ev si EFFLIC file BKG IC file gt jimap_rebin gt rebinned maps ibis background cor ii shadow ubc 2 7 7 og ibis ip shadow ubc ogibis 4 Figure 31 Overview of the binning background step for Lightcurves ISDC IBIS Analysis User Manual Issue 5 1 63 The executable ibis isgr energy performs a rise time correction for each raw ISGRI event using the ISGRI rise time correction table Section B 2 The corrected energy is given in keV ISGRI_ENERGY and the corrected rise time ISGRI PI is the row n
152. s from COR to IMA2 included listed in GENERAL_levelList were performed You can choose what to run according to what kind of output you need Basically e If you are interested only in imaging results set startLevel COR endLevel IMA2 with the complete list of GENERAL_levelList given above as done in section 7 1 e If you have already a catalog of sources for which to extract the spectra e g specat fits and you are not interested in the imaging results anymore you can skip all the imaging related levels and do llspecat fits has to be of the ISGR SRCL RES type meaning that it has to be created by the imaging step with OBS1_DoPart2 1 since this file is created at mosaic stage See section 7 2 to learn how to go from the imaging result file isgri_srcl_res fits to your specat fits to avoid software crash ISDC IBIS Analysis User Manual Issue 5 1 34 startLevel COR endLevel SPE GENERAL_levelList COR GTI DEAD BIN_S SPE Remember that if you do not do the imaging part then isgri_srcl_res fits is not created This file is the default one that is used for spectral extraction 7 2 Do not forget to specify the catalog you have built for this purpose setting the SCW2_cat_for_extract equal to specat fits 1 e Likewise if you are interested only in lightcurve results you should create PIFs for all source of interest with ii_pif program see Section 9 10 for an example and afterwards you may use startLevel COR en
153. si BOON Sedes do dee ae A ea a ek f OAS 72 12GB iu aos A a a RW EG EE RSGGESSSs 72 s duco oc PPP LITT 72 We A See RC OT 75 RA SUMA Sa Qk 9 o9 a s CE Wow w R NOE OLE A wo x 77 TES o on he ae a ee alae eS Re ee RR eS 77 12 9 Speca Anab di escasas eee Ee ESOS Oh EE GE EMER Eee GEES 77 IZU pee eTO duos RE OER EAS A we 77 IX OSTEN ETNO Leda iaa oh E os Roe ee aoe a ae ws AR x XE 79 12 10 Timing Analys oii pror Pe e okox ko 4i R eee bed ddd gd 79 1940 1 a AI 79 121023 m duro aasa a A TT 80 1211 Summing up the resulta oe ca 5 449 49k R3 Ro OYE PEED ED aed GES 80 12 11 1 PARMO E ee RAIN ee He LS Gs 80 12 12 Tools not included in the pipeline o e a 81 12 12 1 Mostiesple a o0 gx do a a a we oe RO Rc ee P odd 81 LOLAS ULA ee AAA A A eee t oe Gs 82 A Low Level Processing Data Products o 84 AL Po UD Rte oc a eS REG BE ee EERE ee PA ed ae ke amp 84 A11 Photon by photon mode en 84 ALZ PICSIT Standard Mode 22 46 Ro bh dee a UR ER ROSA E 84 Au PeBbarOd Did oe Ge Qe ear cr audeo nu A ADAE URN OE bap ara good ROS ap e 85 B Instrument Characteristics used in Data Analysis lll 86 B l Noy PEG ccoo 5G he 6 bom eee HES Rot RUND PES a Be MY a 86 B Calbration Comecions aia ee hen AEA EEE Oe a eS aca 86 B 2 1 POR 2o be Eo e RESCUE a ad 86 B22 PIES CPC me ed Ba AG AE Ee e BEE BS 87 EE Go M oo ee Ge a Be eR ES a ee ee ee Se we 87 BA Instrument Backeround
154. sis Fadl Image Reconstruction o o saoao 1 4 4 Results from the Image Step Val Displaying the Results from the Image Step ISDC IBIS Analysis User Manual Issue 5 1 11 11 12 14 15 18 18 19 20 21 21 21 21 23 23 25 26 iii 1 2 7 3 Spectral Extraction ia 208 os web hw a a AG OR RGROR WO wovon 1 2 1 Results of the Spectral Extraction 222 2054 54 00 RS 22 Displaying the Results of the Spectral Extraction Ligh curve ExtracbioH 20202502 26 PS Ron a a A Tal Results of the Lightcurve Extraction e 1 3 2 Displaying the Results of the Lightcurve Extraction 8 More on ISGRI relevant parameters e 8 1 8 2 8 3 How to choose the start and end level for the analysis ls Imagina ica box 5 020 do od 9 eee A al obs 821 How to choose the source search method in the Science Window analysis 8 2 2 Parameters related to the mosaic step 8 2 3 Background Subtraction s 22223 ox bed eee See eb bbe dee E 8 2 4 Miscellanea on Imaging sn ae ee ee ee Ros Spectral and Timing Analysis so s ce a diaaa 0002 eee eee eee 8 3 1 Spectral Energy Binning se osere ea ee OE Ete ROS RR bee a 8 3 2 Background Subttaction s se 225 608 225444 Es 8 3 3 Iuput catalog aia eoe RAR Oe Oe we HR RR KE 9 Useful recipes for the ISGRI data analysis eee 9 1 9 2 9 3 9 4 9 5 9 6
155. sis you should just launch the main script ibis_science_analysis with a desired set of parameters As discussed in the Overview Section 5 the main script consists of smaller scripts which in turn unify executables with similar tasks for different types of events see Figure 28 In this chapter we describe these small scripts in more detail in order to explain how the main script works and what parameters you have to enter for a proper analysis While describing the executables we describe those parameters which were included into the main script You find in the Appendix the detailed description of the results produced at each step In the Appendix you also find the description of raw and prepared data with which you start the analysis 12 1 ibis correction This script produces corrected Data Structures for all types of the events This script combines the following executables e ibis isgr evis tag e ibis isgr energy e ip ev correction Using the information about the noisy pixels see Section 3 2 3 the script flags all the noisy events Then the script performs the energy correction of all the events for which correction is possible no correction can be done for the spectral timing mode The output Data Structures contain the list of the photon energy in keV see Appendix C 1 12 1 1 ibis isgr evts tag ibis isgr evts tag tags as noisy all photons from a pixel if this pixel had a switch off during the Scw It also looks at the di
156. spextract_pics pl i picsit lst r 83 605 d 21 95 ISDC IBIS Analysis User Manual Issue 5 1 53 n 8 o crabspe_pics fits m pics rmf fits a REP_BASE_PROD ic ibis rsp pics_sarf_rsp_0002 fits In this command switches i and o define the input and output files r and d define the RA and DEC of the desired pixel n defines the number of energy ranges m and a define the locations of rmf and arf matrices First and last channels of the resulting spectrum crabspe pics pha are fictive Do not forget to ignore them The result is shown in Figure 26 data and folded model crabspe_pics f te T T MEM gt Y E eT Gs a 2 Q E E 2 H 3 i m o 9E E E f Qo L c I a 200 500 1000 channel energy keV Figure 26 PICsIT Crab spectrum extracted from the mosaic 10 3 PICsIT pipeline spectral extraction An improvement in the PICsIT spectrum extraction executable with the PIF method has been implemented in the OSA 5 1 and is described below Despite the improvement under certain conditions e g staring observations the algorithm is unstable We suggest that the user adopts the method of extracting spectra from images as explained in Section 10 2 At the moment it is not possible to run the pipeline spectral analysis if you have already executed the BIN_I and IMA2 steps in the group Thus to start spectral analysis move to a new working directory REP BASE PROD obs picsit s
157. ss and strength to overcome the launch environment and the in orbit operational temperatures This panel is done from the material known as nomex Its transparency should be taken into account in the data analysis as it absorbs part of the flux Figure 6 shows the cross section of the support panel The Peripheral Frame reinforces the sandwich panel ISDC IBIS Analysis User Manual Issue 5 1 7 Figure 6 The cross section of the support panel The mechanical interfaces with the INTEGRAL payload module also provide extra Tungsten shielding to the diffuse background through the gap between the mask edges and the payload vertical walls 3 2 2 The Collimator In order to maintain the low energy response of IBIS despite the dithering needed for SPI the collimation baseline consists of a passive lateral shield that limits the solid angle and therefore the cosmic gamma ray background viewed directly by the IBIS detector in the full field of view up to a few hundreds of keV The tube collimation system is implemented with three different devices e The Hopper four inclined walls starting from the detector unit with a direct interface to the IBIS detector mechanical structure The hopper is not physically connected to the payload module structure e The Tube The Tube is formed by four payload module walls shielded with glued Lead foils e The additional side shielding on the mask Four strips of 1 mm thick Tungsten provi
158. stribution of the time between events in each given pixel If this distribution is abnormal all photons from this pixel are flagged as noisy within this Scw Noisy events are ignored in the subsequent analysis Table 3 ibis isgr evts tag parameters included into the main script Name Name Type Description in the main script executable SCW1_ICOR_idxSwitch idxSwitch string DOL of the index of pixels switch list default SCW1_ICOR_probShot probShot real Probability of shot time decay default 0 01 12 1 2 ibis isgr energy Due the charge loss in the CdTe crystal for a given energy deposit events which have interacted at different depths in the crystal get different measured amplitudes PHA The rise time of the signal induced by these events is also different and a clear quasi linear correlation between the charge loss and the rise time variation is observed a deeper interaction induces a larger charge loss giving the longer rise time It is then possible to correct this charge loss effect by taking into account the rise time information of the signal ISDC IBIS Analysis User Manual Issue 5 1 61 ibis science analysis ibis correction i ibis_isgr evis_tag Y P HE LE sew ibis_isgr_energy sew K l I H IB energy correclion jp ey correction 2 i 1 1 1 i 1 om Ug gti create 3 i El IZ y gti attitude AL M E gti definition gti
159. t of images List of sources for a given ScW found the Figure 14 Overview of the IMA level products You find more details on the structure of the output files in Section C 7 1 7 1 2 Displaying the Results from the Image Step It is convenient to look at the images with the help of the ds9 program First create a region file from the catalog using the cat2ds9 program In the example below we create the region file found reg with all the sources found in the mosaic image isgri_mosa_res fits for the first energy band extension number 2 and a region file cat reg with all sources that were in the input catalog isgri_catalog fits cd REP_BASE_PROD obs isgri_gc cat2ds9 isgri_mosa_res fits 2 found reg symbol box color green cat2ds9 isgri_catalog fits 1 cat reg symbol box color white To see the resulting images ds9 REP_BASE_PROD obs isgri_gc isgri_mosa_ima fits 2 region REP_BASE_PROD obs isgri_gc cat reg cmap b scale sqrt scale limits 0 60 zoom 2 REP BASE PROD obs isgri gc isgri mosa ima fitsN 4 N region REP BASE PROD obs isgri gc found regN cmap b scale sqrt scale limits 0 60 zoom 2 In Figure 16 you see the intensity REP BASE PROD obs isgri gc isgri mosa ima fits 2 left and sig nificance REP BASE PROD obs isgri gc isgri mosa ima fits 4 right mosaic images in the 20 40 keV energy range In the left image we have shown all catalog sources white boxes and in the right one only the detected one
160. t of lower energy boundaries for PICsIT multiple events default 300 600 1000 IBIS IP E band max s picsit e max m string List of higher energy boundaries for PICsIT multiple events default 600 1000 13500 SCW1_BIN_P inDead inDead string DOL of the dead time Data Structure default SCW1_BIN_P faltStatus faltStatus string DOL of the list of faulty pixels default 12 4 3 ip si shadow build ip si shadow build takes as an input PICsIT data received in standard mode For each given energy and time range intensity and efficiency shadowgrams are produced Efficiency is defined as Ef 1 EX D Ton T Table 13 ip_si_shadow_build parameters included into the main Script Name Name Type Description in the main script executable IBIS IPS ChanNum picsit e bin integer Number of Energy bands 0 means to use the default ones default 0 IBIS_IPS_E_band_min picsit e min string List of lower energy boundary default 170 600 1000 IBIS IP E band max picsit e max string List of higher energy boundary default 600 1000 10000 SCW1_BIN_P_inDead inDead string DOL of the dead time Data Structure default ISDC IBIS Analysis User Manual Issue 5 1 69 12 5 1i_map_rebin ii map rebin reads input background and or Off axis correction maps and rebins them into new energy bands Background maps are summed with coefficients equ
161. t with time bin less than about 60 seconds Besides be aware that the higher the number of total bins is the higher is the time and space needed The i light tool not called in the analysis script but available as a stand alone tool uses a different algorithm the lightcurve is extracted not via the shadowgram creation but with the use of the Pixel Illuminated Fraction PIF This allows to extract lightcurves up to a time bin of about 0 1 sec This is not the official lightcurve extraction tool and should be used mainly to check relative variability of bright sources within a given Science Window rather than for a long term absolute flux estimate Note that to be able to run Z light you need to have ROOT available ISDC IBIS Analysis User Manual Issue 5 1 45 9 9 2 Run ii_light To be able to use 4i light you have to run the standard analysis until the SPE level startLevel COR endLevel SPE You need to run the IMA level with the same energy ranges in which you are going to extract the lightcurves This is due to the fact that the IMA step will produce correction and background maps rebinned_corr_ima fits and rebinned back ima fits that are energy dependent and that will be put as input to ii light Alternatively you can use ii_map_rebin to produce these maps inthe desired energy bands You need to run the SPE level because during this level the PIF needed as input to 21_light is created Alternatively you can create PIF with di pif pr
162. tension of the file scw 0051004X0010 001 isgri spectrum fits 1 is an index summarising the content of all the extensions With the help of this index you can easily see which extension contains the spectrum of the source you are interested in To achieve a better signal to noise ratio it can be convenient to sum up spectra of a source from different science windows This can be done with the spe_pick tool In the following example we create a joint spectrum of 4U 1700 377 from all the available science windows included in the og ibis fits file cd REP_BASE_PROD obs isgri_gc spe pick group og ibis fits 1 source 4U 1700 377 rootname 4U1700 As a result two files with spectra of 4U 1700 377 will be created 4U1700 sum pha fits contains the final average spectrum of 4U 1700 377 while 4U1700_single_pha2 fits stores all the original spectra of 4U 1700 377 that were used to create the average one It is forseen that in the nearest future there will be several ARFS depending on the data time In order to deal with the data from different time periods spe pick was updated and creates now a resulting ARF for your particular dataset This ARF is written to 4U1700 sum arf fits and 4U1700 single arf fits files At the moment only one ARF is present and is copied as it is to the files mentioned above 7 2 2 Displaying the Results of the Spectral Extraction To analyze the average spectrum with XSPEC do cd REP BASE PROD obs isgri gc fparkey 0
163. the command line typing name value after the script name If you are running your own scripts that call OSA many times you don t want GUI to pop up each time In such a case set COMMONSCRIPT variable to 1 with setenv COMMONSCRIPT 1 This is automatically done within the file created with the help of Save as button see above To have the GUI back again unset the variable unsetenv COMMONSCRIPT 6 4 Useful to know e How do I get some help with the executables All the available help files are stored under ISDC_ENV help To visualize a help file interactively type tool_name h once your environment is set i e which tool_name returns the path to it e Where are the parameter files and how can I modify them All the available executables for the analysis of INTEGRAL data are under ISDC_ENV bin The corresponding parameter files are stored under ISDC_ENV pfiles par The first time you launch a script the system will copy the specific tool par from ISDC_ENV pfiles to a local directory user_ name pfiles The parameter file in the local directory is the one used for the analysis and is ISDC IBIS Analysis User Manual Issue 5 1 21 the one you can modify If this parameter file is missing e g you have deleted it the system will just re copy it from ISDC_ENV pfiles as soon as you launch the script again The system knows what to copy from where thanks to the PFILES environment variable that is
164. the ghosts of all the sources in the field of view It is of course more time consuming since a model is created and deconvolved for each given source We suggest that you should use this mode either with your own catalog built from the previous run with OBS1 SearchMode 2 see above or if no personalised catalog is available using the ISDC catalog with only the sources that have been detected by ISGRI 1SDC REF CAT ISGRI_FLAG 1 see above Any bright source out of the catalog new or forgotten will be detected as one of the K new sources 8 2 2 Parameters related to the mosaic step The 0B81 SearchMode parameter concerns only images at a Science Window level In the mosaic image the software always looks for K 0BS1 ToSearch sources more significant than OBS1_MinCatSouSnr for catalog sources or OBS1 MinNewSouSnr for the new sources regardless the real number of sources in the field of view Thus if you are working with a crowded part of the sky mainly Galactic plane and Centre you should use a high OBSI ToSearch number at least 20 There are two ways to calculate the source flux in the mosaic given the original Science Window information e OBS1_PixSpread 0 The whole input Science Window pixel count is put into one output mosaic pixel no spread is done This method optimises the flux and signal to noise ratio SNR evaluation but can sometimes give some undesired effects such as double source peaks e OBS1 PixSpre
165. truct the image The actual sky coverage in an observation of course depends on the dither pattern The on board electronics classify registered events according to the activated layer and the number of events detected by a submodule practically simultaneously Events detected by different submodules are treated as independent ones There are five main events type e ISGRI single event Photon is stopped in a single pixel of the ISGRI layer generating an electric pulse In principle the amplitude of the pulse yields the energy of the incident photon However above 50 keV the energy is a function of not just the pulse height but also the pulse rise time so both are used to determine the energy of the incident photon In addition the resulting line profile energy resolution is no longer Gaussian but more similar to a Lorentzian The energy resolution depends on the operating temperature and also on the bias voltage the bias voltage has to be optimized as a trade off between high resolution but more noise high voltage or lower noise but lower resolution low voltage All cases of multiple ISGRI detection units excitation in one module are rejected In case of the excitation of the detection units in different modules such events are treated as independent single events e PICsIT single event Photon passes through ISGRI and is stopped in a single pixel of the PICsIT layer generating one scintillation flash The energy of the incident
166. ue source identifier NAME One commonly used name for the source RA_FIN Source right ascension in degrees DEC_FIN Source declination in degrees FIN RD ERR Error of the fine position of the source in RA and DEC Y FIN Y axis fine position of the source in pixels Z_FIN Z axis fine position of the source in pixels FIN_YZ_ERR Error of the fine position along Y and Z axis in pixels DETSIG Source detection significance in ISGRI E_MIN Lower energy boundaries E MAX Upper energy boundaries FLUX Flux values FLUX ERR Flux errors DEADC Mean deadtime and greyfilter correction factor EXPOSURE Mean exposure time over the detector plane ISDC IBIS Analysis User Manual Issue 5 1 94 TSTART Start time of the observation IJD TSTOP End time of the observation IJD C 7 2 ip skyimage ip skyimage performs deconvolution of the PICsIT shadowgrams with the use of the balanced cross correlation method described in Goldwurm et al 2003 10 see also Section 12 8 The values of the decoding G array are taken from PICS DECO MOD Data Structure The output Data Structure PICS SKY IMA store either a cartesian CAR or a tangential TAN pro jection of the celestial sphere The index of deconvolved images is written to the PICS SKY IMA IDX Data Structure it has the same content as ISGR SKY IMA IDX Table 49 IMATYPE can be either IMAGE either VARIANCE or SIGNIFICANCE The list of sources that were found during the analysi
167. umber used in the IC file The correction is done by rescaling the measured spectra in accordance with the observed rise time rt so that the corrected event corresponds to the deposited energy Also the temperature and bias corrections are done at this step Table 4 ibis_isgr_energy parameters included into the main script Name Name Type Description in the main script executable SCW1ICOR_GODOL GODOL string DOL of the Gain Offset correction table default gt SCWI1ICOR riseDOL riseDOL string DOL of the rise time correction table default gt SCW1_ICOR_icDOL icDOL string DOL of the IC file for calibration parameters default gt 12 1 3 p ev correction The executable 2p ev correction performs energy correction of the events received by PICsIT in photon by photon mode Single events are corrected for each pixel separately with the use of the pixel dependent gain and offset factors and the pixel independent channel to keV conversion factors avgain and avoffset see Section B 2 for more details energy keV avgain gain PICSIT PHA avoffset offset Multiple events are corrected for gain and offset on board and thus they are simply transferred from channels to keV energy keV avgain PICSIT PHA Table 5 ip_ev_correction parameters included into the main script Name Name Type Description in the main script executable SCWI1 PCOR enerDOL ener
168. w we create a file 4U1700 377 scwlc fits with all the information on 4U 1700 377 in 20 40 keV energy band The structure of this file is explained in Appendix C 7 Table 53 src_collect group og ibis fits i results 4U1700 377 scwlc fits instName ISGRI select NAME 4U 1700 377 amp amp E MIN 20 In Figure 17 the 20 40 keV science window per science window 4U 1700 377 lightcurve is shown 7 2 Spectral Extraction It is not possible to extract the spectrum of only the source you are interested in All sources brighter or compatible with the one you are interested in should be taken into account too Thus it is strongly recommended when you deal for the first time with your data to run the analysis until the IMA2 level as described in Section 7 1 check the results and call bis_science_analysis once again to run the spectral extraction part The description of the algorithm used for spectral extraction is given is Section 12 9 1 Launch ibis science analysis and on the main GUI page change Start Level to BIN S and End Level to SPE After that press the ISGRI SPE and LCR button On the screen that appears see Figure 18 you can specify Spectral energy binning ISDC IBIS Analysis User Manual Issue 5 1 27 Figure 16 Intensity left and significance right mosaic in the 20 40 keV energy band With the help of the parameter IBIS_SI_inEnergyValues you can specify the file and its extension de sc
169. you to create the mosaic separately from the main analysis see Section 7 1 for the details The Parameter PixSpread sets whether the source flux is spread or not in the mosaic image No spread mosaic puts the whole input pixel count into one output map pixel It permits better flux and signal to noise ratio approximation as each pixel count and variance is summed without any error On the other hand it can give some undesired effects as double source peaks because of binning In the spread mosaic the input pixel count is spread between some number of output map pixels This method is better for source position recovery but not so good for source flux estimation because of the source peak height reduction Furthermore neighbouring pixels in the individual Science Window images are correlated and correct spread variance calculations should take this into account But as exact calculation of the covariance matrix is too heavy for on line analysis the approximative variance formula is used The i skyimage parameters are given in the Table 18 Table 18 ii skyimage parameters included into the main script Name Name Type Description in the main script executable OBS1 mask mask string DOL of the MASK pattern fits file default OBS1_deco deco string DOL of the projected decoding pattern fits file default gt OBS1_DataMode DataMode integer Data Simulation mode possible values 0 shadowgrams are treated 1

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