Bugs: acis_process_events

A list of bugs fixed in CIAO 3.4 is available.

Caveats

1. Aspect files must be arranged in chronological order

2. CONTENT keyword value is set to "EVT1" (14 Feb 2007)

Bugs

1. Status bits in the input file are not reset when reprocessing data

2. PHA_RO value in reprocessed files (06 Mar 2007)

3. Stop-time for afterglow bad pixels (06 Mar 2007)

Caveats

1. Aspect files must be arranged in chronological order

   acis_process_events assumes that the aspect files given in the acaofffile and alignmentfile parameters are arranged in chronological order. If the files are not in order, the tool will exit with an error.

   If you have not altered the original filenames, a simple "ls" will put them in order, as the time is listed in the filename:

   unix% pwd
   /data/459/primary
   
   unix% ls -1 pcad*
   pcadf063874624N002_asol1.fits
   pcadf063875522N002_asol1.fits
   pcadf063902942N002_asol1.fits
   

   Otherwise, get the value from the TSTART header keyword:

   unix% dmkeypar pcad_1.fits TSTART echo+
   63875522.3455031
   

   and put the files in chronological order.

2. CONTENT keyword value is set to "EVT1" (14 Feb 2007)

   acis_process_events always sets the CONTENT keyword in the output file to "EVT1", regardless of whether the input is an evt1.fits or evt2.fits file. (Note that there are only specific cases in which an evt2 file may be used as input to acis_process_events.)

   Workaround:

   While the CONTENT value will not negatively affect any analysis downstream, users can change the value with dmhedit if they so choose.

Bugs

1. Status bits in the input file are not reset when reprocessing data

   When acis_process_events is used to reprocess event data, it does not unset status bits in the input data file. For example, acis_process_events does not recalculate the bad pixel status bits. If events have status bits set in the input event file, then the values are always copied to the same bits in the column STATUS of the output file. If the badpixfile is set to a value other than "NONE" (the default), then only additional status bits can be set in the output file. This limitation will be fixed in a future release.

2. PHA_RO value in reprocessed files (06 Mar 2007)

   After the a file is reprocessed, the values of PHA_RO in the output file are equal to the values of PHA (after the CTI and tgain adjustments) in the original file. They should be equal to the summed pulse height of the original, unadjusted event island (PHAS).

   Note that the PHA_RO values are not used by any CIAO tool be default, so this should not affect subsequent analysis steps.

3. Stop-time for afterglow bad pixels (06 Mar 2007)

   There is a bug where the stop-time of afterglow badpixels is not being correctly used. Once marked as bad, the afterglow badpixels are continued to be marked as bad (bit 16) until the end of the observation.

Bugs fixed in CIAO 3.4

The following is a list of bugs that were fixed in the CIAO 3.4 software release.

1. Pixels identified as having bias values that are too high or too low are not recorded in the STATUS column of the event file.

   acis_process_events should set bit 4 in this case. The bias value pixels are correctly recorded in STATUS bit 16 of the bad pixel file (bpix1.fits).