LETG/ACIS-S Grating ARFs

CIAO 4.2 Science Threads

Overview

Last Update: 5 Apr 2010 - updated for CALDB 4.2.1: calibration update - the LETG grating efficiency has been upgraded to vN0006.

Synopsis:

fullgarf is a script that creates a grating ARF for a particular order and grating of an observation. While the mkgarf tool will create a grating ARF for an individual chip given an aspect histogram, this script creates ARFS for each chip, creating aspect histograms as necessary. The script then combines the individual ARFS into one for the full array.

Purpose:

To create grating ARFs for an LETG/ACIS-S observation.

Read this thread if:

you are working with an LETG/ACIS-S observation and intend to model and fit the spectra.

Calibration Updates:

• CALDB v4.2.1 (5 Apr 2010):

  The LETG grating efficiency file (GREFF) was updated to be version N0006. The new file will be used by default when creating LETG response files (ARFs).

  There is no change in the responses for +/1 order. The revised effective area curves (ARF files) for orders 2-7 will be lower than those created with the previous LETG GREFF calibration by 3-9%.

  Users should read the How CALDB 4.2.1 Affects Your Analysis section of the CIAO 4.2 release notes for more information on how this change will affect the response file.

• CALDB v4.2.0 (15 Dec 2009):

  The ACIS QE contamination model has been upgraded to vN0005. This version of the file contains separate components for the correction on ACIS-S and ACIS-I. The new calibration file is used by default when creating ARFs and instrument maps in CIAO 4.2.

  The changes in the vN0005 file will primarily affect low-energy absorption components between C-K edge (0.283 keV) and 1.2 keV. In general, hard spectra will not be affected much by the calibration change.

  Users should read the ACIS QE Contamination Model vN0005 section of the CIAO 4.2 release notes for information on how this change will affect the response file.

Related Links:

• Analysis Guide for Chandra High Resolution Spectroscopy: an in-depth discussion of grating analysis.

• Continuous Clocking Mode why topic: additional information for users working with CC-mode data.

• ACIS QE Contamination why topic: correcting for the change in low-energy ACIS QE associated with the deposition of one or more materials on the ACIS detectors or optical blocking filters.

Parameters for /home/username/cxcds_param/fullgarf.par


       phafile = acisf01198N002_pha2.fits Input PHA file (Type I or II)
        pharow = 2                Row in Type II PHA file (ignored if Type I)
       evtfile = acisf01198N002_evt2.fits Event file 
          asol = @pcad_asol1.lis  Aspect offsets file
        engrid = grid(rmf.fits[cols ENERG_LO,ENERG_HI]) Energy grid spec
       dtffile = )evtfile -> acisf01198N002_evt2.fits Dead time correction factor; ACIS->evt file; HRC -> dtf file
        badpix = acis_1198_new_bpix1.fits Bad pixel file; (filename|NONE|CALDB)
      rootname = acisf01198       Output rootname
      maskfile = acisf01198_000N002_msk1.fits NONE, or name of ACIS window mask file
      pbkfile  = acisf063833861N002_pbk0.fits NONE, or the name of the parameter block file
       (dafile = CALDB)            NONE, CALDB, or name of ACIS dead-area calibration file
     (osipfile = CALDB)           NONE or Name of fits file with order sorting info
      (clobber = no)              Clobber existing output files? This is passed to ALL child processes.
      (verbose = 0)               Control the level of diagnostic output. 0=>least.
         (mode = hl)              Mode flags.  Set to 'ql' to enable querying, 'hl' to suppress.