Step-by-Step Guide to Creating ACIS Spectra for Pointlike Sources

Overview

Last Update: 14 Jun 2006 - corrected link in "Calibration Updates"; clarified information on GRADED mode data

Synopsis:

Using a combination of CIAO tools, we extract source and background spectra for a pointlike source. The background spectrum is grouped, if desired. The appropriate Response Matrix Files (RMFs) and Ancillary Response Files (ARFs) are also created for both source and background.

Purpose:

To generate source and background PI (PHA) spectra of a pointlike ACIS source and build the proper RMFs and ARFs.

Read this thread if:

you are working with any ACIS observation, whether imaging or grating data.

Calibration Updates:

• CALDB v3.2.1 (15 Dec 2005): The gain for the back-illuminated (BI) chips - ACIS-S1 and S3 - for -120 GRADED mode observations has been upgraded. It is now possible to use mkacisrmf when creating responses for these chips only in GRADED mode. See How CALDB 3.2.1 Affects Your Analysis for details.
• CALDB v3.2.0 (21 Nov 2005): The version 5 "phase 2" response file (acisD2000-01-29p2_respN0005.fits) was added to CALDB 3.2.0, released on 21 November 2005. Information on the changes in CALDB 3.2.0 is in the How CIAO 3.3 and CALDB 3.2.0 Affect Your Analysis section of the CIAO release notes.
• CALDB v3.1.0 (23 Jun 2005): The version 4 "phase 2" response file (acisD2000-01-29p2_respN0004.fits) was added to the CALDB. In conjunction with the ACIS CTI and TGAIN calibration improvements in this CALDB release, the mkacisrmf tool can now be used to create RMFs for all -120 observations, except for those done in GRADED mode.
• CALDB v2.26 (20 Feb 2004): New FEF files containing updated information for ACIS S3 were added to the CALDB; there are CTI-corrected and uncorrected versions available. The ACIS contamination files were also included in this update.
• CALDB v2.21 (14 Feb 2003): The new CTI-corrected FEF file (acisD2000-01-29fef_pha_ctiN0002.fits) contains updated information for chips S0, S1, and S3-5, eliminating the calibration problem announced in December 2002. Applying the CTI correction to these chips will no longer have a negative effect on the data.
• CALDB v2.8 (13 Sep 2001): New OSIP files make it possible to analyze -120 degrees S3 grating data with the gainmaps and FEFs that were in the prevous CALDB release. If you are working with an observation taken under these conditions, run the Apply an ACIS Gain Map thread before running this thread. If you need help determining the temperature of your observation, see this FAQ.

Related Links:

• Using psextract to Extract ACIS Spectra and Response Files for Pointlike Sources: the automated version of this thread.

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


#--------------------------------------------------------------------
#
# DMEXTRACT -- extract columns or counts from an event list
#
#--------------------------------------------------------------------
        infile = acisf00459N002_evt2.fits[sky=region(3c273_bg.reg)][bin pi] Input event file 
       outfile = 3c273_bg.pi      Enter output file name
          (bkg = )                Background region file or fixed background (counts/pixel/s) subtraction
        (error = gaussian)        Method for error determination(poisson|gaussian|<variance file>)
     (bkgerror = gaussian)        Method for background error determination(poisson|gaussian|<variance file>)
      (bkgnorm = 1.0)             Background normalization
          (exp = )                Exposure map image file
       (bkgexp = )                Background exposure map image file
      (sys_err = 0)               Fixed systematic error value for SYS_ERR keyword
          (opt = pha1)            Output file type: pha1 
     (defaults = ${ASCDS_CALIB}/cxo.mdb -> /soft/ciao/datacxo.mdb) Instrument defaults file
         (wmap = )                WMAP filter/binning (e.g. det=8 or default)
      (clobber = no)              OK to overwrite existing output file(s)?
      (verbose = 0)               Verbosity level
         (mode = ql)              
    

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


        infile = acisf00459N002_evt2.fits[sky=region(3c273.reg)][cols chipx,chipy,ccd_id,x,y] Input file specification
   out_columns = chipx,chipy,ccd_id,x,y Output Column Label
       out_min = 258,350,7,4138.965332,4034.1166992 Output Minimum Value
   out_min_loc = 224,726,1,64,394 Output Minimum Location Value
       out_max = 309,394,7,4157.6948242,4052.0361328 Output Maximum Value
   out_max_loc = 258,142,1,484,26 Output Maxiumum Location Value
      out_mean = 280.28940217,373.73097826,7,4146.0548958,4045.9470477 Output Mean Value
    out_median =                  Output Median Value
     out_sigma = 12.242530849,11.837941816,0,3.5179725102,3.8411838536 Output Sigma Value
       out_sum = 206293,275066,5152,3051496.4033,2977817.0271 Output Sum of Values
      out_good = 736,736,736,736,736 Output Number Good Values
      out_null = 0,0,0,0,0        Output Number Null Values
    out_cnvrgd =                  Converged?
 out_cntrd_log =                  Output Centroid Log Value
out_cntrd_phys =                  Output Centriod Phys Value
out_sigma_cntrd =                  Output Sigma Centriod Value
     (centroid = yes)             Calculate centroid if image?
       (median = no)              Calculate median value?
        (sigma = yes)             Calculate the population standard deviation?
         (clip = no)              Calculate stats using sigma clipping?
       (nsigma = 3)               Number of sigma to clip
      (maxiter = 20)              Maximum number of iterations
         (mode = ql)              
    

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


        infile = CALDB            scatter/rsp matrix file
       outfile = 3c273_bg_mkacisrmf.rmf RMF output file
          wmap = 3c273_bg.pi      WMAP file
        energy = 0.1:11.0:0.01    energy grid in keV (lo:hi:bin)
       channel = 1:1024:1         channel grids in pixel (min:max:bin)
      chantype = PI               channel type
        ccd_id =                  filter CCD-ID
         chipx =                  filter chipx in pixel
         chipy =                  filter chipy in pixel
          gain = CALDB            gain file
      (logfile = )                log file
      (contlvl = 100)             # contour level
      (geompar = geom)            pixlib geometry parameter file
       (thresh = 1e-6)            low threshold of energy cut-off probability
      (clobber = no)              overwrite existing output file (yes|no)?
      (verbose = 0)               verbosity level (0 = no display)
         (mode = ql)              
    

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


#--------------------------------------------------------------------------
#
#       Parameter file for the ASPECT HISTOGRAM Tool
#
#--------------------------------------------------------------------------
        infile = @pcad_asol1.lis  Aspect Solution List Files
       outfile = 3c273.asphist    Aspect Histogram Output File
       evtfile = acisf00459N002_evt2.fits[ccd_id=7] Event List Files
       dtffile =                  Live Time Correction List Files for HRC
      (geompar = geom)            Parameter file for Pixlib Geometry files
       (res_xy = 0.5)             Aspect Resolution x and y in arcsec
     (res_roll = 600.)            Aspect Resolution roll in arcsec
      (max_bin = 10000.)          Maximal number of bins
      (clobber = no)              Clobber output
      (verbose = 0)               Verbose
         (mode = ql)              
    

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


   asphistfile = 3c273.asphist[ASPHIST] Aspect Histogram File
       outfile = 3c273_bg.arf     Output File Name
  sourcepixelx = 4144.86          Source X Pixel
  sourcepixely = 4032.65          Source Y Pixel
        engrid = grid(3c273_bg.rmf[cols ENERG_LO,ENERG_HI]) Energy grid spec
       obsfile = )asphistfile -> 3c273.asphist[ASPHIST] Name of fits file with obs info (include extension)
     detsubsys = ACIS-S3          Detector Name
       grating = HETG             Grating for zeroth order ARF
      maskfile = NONE             NONE, or name of ACIS window mask file
       verbose = 0                Verbosity
       (mirror = HRMA)            Mirror Name
#
(ardlibparfile = ardlib.par)      name of ardlib parameter file
      (geompar = geom)            Parameter file for Pixlib Geometry files
      (clobber = no)              Overwrite existing files?
#
         (mode = ql)              Enter mode for parameter file.
    

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


        infile = acisf00459N002_evt2.fits   Source file (event or spectrum)
        chipid = 7                ACIS chip number
         chipx = 290              ACIS chip x coordinate
         chipy = 379              ACIS chip y coordinate
      (outfile = /soft/ciao/CALDB/data/chandra/acis/cpf/fefs/
acisD1999-09-16fef_phaN0002.fits[FUNCTION][ccd_id=7,chipx=289:320,chipy=353:384]) FEF file to use
      (verbose = 0)               Verbose level
         (mode = ql)              
    

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


        infile = /soft/ciao/CALDB/data/chandra/acis/cpf/fefs/
acisD1999-09-16fef_phaN0002.fits[FUNCTION][ccd_id=7,chipx=289:320,chipy=353:384] name of FEF input file
       outfile = 3c273_bg.rmf     name of RMF output file
         axis1 = energy=0.1:11.0:0.01 axis-1(name=lo:hi:btype)
         axis2 = pi=1:1024:1      axis-2(name=lo:hi:btype)
      (logfile = STDOUT)          name of log file
      (weights = )                name of weight file
       (thresh = 1e-5)            low threshold of energy cut-off probability
       (outfmt = legacy)          RMF output format (legacy|cxc)
      (clobber = no)              overwrite existing output file (yes|no)?
      (verbose = 0)               verbosity level (0 = no display)
        (axis3 = none)            axis-3(name=lo:hi:btype)
        (axis4 = none)            axis-4(name=lo:hi:btype)
        (axis5 = none)            axis-5(name=lo:hi:btype)
         (mode = ql)              
    

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


        infile = 3c273.pi         Input dataset name
       outfile = 3c273_grp.pi     Output dataset name
     grouptype = NUM_CTS          Grouping type
  grouptypeval = 15               Grouping type value
       binspec =                  Binning specification
       xcolumn = channel          Name of x-axis
       ycolumn = counts           Name of y-axis
      (tabspec = )                Tab specification
    (tabcolumn = )                Name of tab column
     (stopspec = )                Stop specification
   (stopcolumn = )                Name of stop column
    (errcolumn = )                Name of error column
      (clobber = no)              Clobber existing output file?
      (verbose = 0)               Verbosity level
    (maxlength = 0)               Maximum size of groups (in channels)
         (mode = ql)              
    

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


        infile = 3c273_bg.pi      Input dataset name
       outfile = 3c273_bg_grp.pi  Output dataset name
     grouptype = BIN              Grouping type
  grouptypeval = 0                Grouping type value
       binspec = 1:1024:20        Binning specification
       xcolumn = channel          Name of x-axis
       ycolumn = counts           Name of y-axis
      (tabspec = )                Tab specification
    (tabcolumn = )                Name of tab column
     (stopspec = )                Stop specification
   (stopcolumn = )                Name of stop column
    (errcolumn = )                Name of error column
      (clobber = no)              Clobber existing output file?
      (verbose = 0)               Verbosity level
    (maxlength = 0)               Maximum size of groups (in channels)
         (mode = ql)