The SWIFT BAT Software Guide Version 6.3 30 ... - HEASARC - Nasa

iv CONTENTS
6 BAT Analysis Issues 55
6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
6.2 Current Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
6.2.1 batoccultgti: Fails when checking the field of view only . . . . . . . . . . . . 55
6.2.2 batbinevt: ignores standard 4-channel energy bins . . . . . . . . . . . . . . . 56
6.2.3 batbinevt: DPH rows with fractional exposure are not accounted for properly 56
6.2.4 batcelldetect: newly detected sources may be deleted . . . . . . . . . . . . . . 57
6.2.5 batcelldetect: the correct point spread function is gaussian . . . . . . . . . . 58
6.2.6 Analysis: Passive materials distort the off-axis counts/rates . . . . . . . . . . 58
6.2.7 batfftimage and batmaskwtimg: potentially incorrect derived attitude . . . . 59
6.2.8 Analysis: Earth and Moon Occultation . . . . . . . . . . . . . . . . . . . . . 59
6.3 Old Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
6.3.1 Analysis: Users must apply systematic error vector for spectral fitting . . . . 60
6.3.2 batmaskwtevt: Slewing Raytracing Keywords Potentially Incorrect . . . . . . 61
6.3.3 Analysis: filtering out non-gamma-ray events may improve sensitivity . . . . 62
6.3.4 SDC: BAT data from SDC pipeline has incorrect DATE-OBS/END keywords 62
6.3.5 batoccultmap: incorrect exposure correction . . . . . . . . . . . . . . . . . . . 63
6.3.6 batbinevt: light curves have slightly incorrect energy bins . . . . . . . . . . . 64
6.3.7 Mask tagged light curve systematic flux errors . . . . . . . . . . . . . . . . . 64
6.3.8 XSPEC crashes with segmentation fault with BAT spectra . . . . . . . . . . 65
6.3.9 baterebin: Possible extra rows in EBOUNDS extension of output DPH . . . . 65
6.3.10 batbinevt: Incorrect exposure for survey analysis . . . . . . . . . . . . . . . . 66
6.3.11 CALDB: Incorrect Spectral Response < 20 keV . . . . . . . . . . . . . . . . . 66
6.3.12 CALDB: Incorrect Alignment Matrix . . . . . . . . . . . . . . . . . . . . . . . 66
6.3.13 batbinevt: Incorrect EXPOSURE Keyword . . . . . . . . . . . . . . . . . . . 67
6.3.14 batcelldetect: Incorrect Error Bars . . . . . . . . . . . . . . . . . . . . . . . . 67
6.3.15 batbinevt: Incorrect Handling of float point DPHs . . . . . . . . . . . . . . . 68
6.3.16 batmasktaglc: light curve error bars too small . . . . . . . . . . . . . . . . . . 68
6.3.17 batmaskwtevt/batmaskwtimg: High-Energy Background Contamination . . . 68
A BAT Data Formats 69
A.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
A.2 File Naming Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
A.3 Event Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
A.4 Survey Detector Plane Histograms . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
A.5 Rate Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
A.5.1 One-second Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
A.5.2 Quadrant Rates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72