LETG/HRC-I Grating ARFs
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CIAO 4.0 Science Threads
OverviewLast Update: 23 Jan 2008 - updated for CIAO 4.0: parameter file update for mkgarf (obsfile parameter is set to event file instead of aspect histogram file); updated ChIPS syntax; removed outdated calibration updates; filenames and screen output updated for reprocessed data (version N005 files) Synopsis: mkgarf creates a grating ARF for a particular order and grating of an observation. Purpose: To create grating ARFs for an LETG/HRC-I observation. Read this thread if: you are working with an LETG/HRC-I observation and intend to model and fit the spectra. Related Links:
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Contents
- Get Started
- Determine Orders
- Compute the Aspect Histogram (asphist)
- Get Source Position (dmlist)
- Run mkgarf
- Summary
- Parameter files:
- History
- Images
Get Started
Sample ObsID used: 1801 (LETG/HRC-I, PKS2155-304)
File types needed: evt2; pha2; asol1; bpix1; dtf1
If you created a new bad pixel file by running the New Observation-Specific HRC Bad Pixel File thread, make sure that you have set up ardlib to use the same bad pixel file.
Determine Orders
An ARF needs to be calculated for each order in the observation. We can use Prism to examine the pha2 file and determine how many orders there are:
unix% prism hrcf01801N005_pha2.fits &
The tg_m column indicates the order of the observation (+/- 1, +/- 2,
+/- 3) and the tg_part column indicates the grating (1 = HEG, 2 = MEG,
3 = LEG). In this example ![[Link to Image 1: PHA2 file displayed in prism]](../../imgs/imageicon.gif){kind=small}
,
there are two rows for the LETG observation. HRC-I cannot resolve
orders; +/- 1 refer to the total positive- and negative-side
counts respectively.
Compute the Aspect Histogram (asphist)
The aspect solution files are used to create a binned histogram detailing the aspect history of the observation:
unix% punlearn asphist unix% pset asphist infile=pcadf082337011N003_asol1.fits unix% pset asphist outfile=asphist.fits unix% pset asphist evtfile="hrcf01801N005_evt2.fits[chip_id=0]" unix% pset asphist dtffile=hrcf01801_000N005_dtf1.fits unix% asphist Aspect Solution List Files (pcadf082337011N003_asol1.fits): Aspect Histogram Output File (asphist.fits): Event List Files (hrcf01801N005_evt2.fits[chip_id=0]): Live Time Correction List Files for HRC (hrcf01801_000N005_dtf1.fits): # asphist (CIAO 4.0): WARNING: skipping 8 livetime correction records (from time: 82336842.920992 to time: 82337011.020998)
In many cases there will be more than one asol1.fits file for an observation. All the files must be input to the infile parameter, either as a list or as a stack (see ahelp stack for more information).
The content of the parameter file may be checked using plist asphist.
Get Source Position (dmlist)
The source position is required as one of the inputs to mkgarf. This information can be easily obtained from the PHA2 file with dmlist:
unix% dmlist "hrcf01801N005_pha2.fits[SPECTRUM][cols x,y]" opt=data rows=1 -------------------------------------------------------------------------------- Data for Table Block SPECTRUM -------------------------------------------------------------------------------- ROW X Y 1 16500.17968750 16366.7568359375
The source in this example is located at (16500.17968750, 16366.7568359375).
Run mkgarf
Now we have all the information needed to run mkgarf. We will have to run the tool twice, once for each row in the PHA file:
A. For row 1, LEG, order = -1
unix% punlearn mkgarf unix% pset mkgarf outfile=1801_-1_LEG_garf.fits unix% pset mkgarf order=-1 unix% pset mkgarf asphistfile="asphist.fits[ASPHIST]" unix% pset mkgarf obsfile="hrcf01801N005_evt2.fits[EVENTS]" unix% pset mkgarf engrid="grid(rmf.fits[cols ENERG_LO,ENERG_HI])" unix% pset mkgarf detsubsys=HRC-I grating_arm=LEG unix% pset mkgarf sourcepixelx=16500.17968750 sourcepixely=16366.7568359375 unix% mkgarf Aspect Histogram File (include extension) (asphist.fits[ASPHIST]): Output File Name (1801_-1_LEG_garf.fits): Enter Grating order (-1): Source X Pixel (16500.17968750): Source Y Pixel (16366.7568359375): Energy grid spec (grid(rmf.fits[cols ENERG_LO,ENERG_HI])): Name of fits file with obs info (include extension) (hrcf01801N005_evt2.fits[EVENTS]): NONE or Name of fits file with order sorting info (NONE): Detector Name (HRC-I): Enter Grating Arm (HEG|MEG|LEG) (LEG): NONE, or name of ACIS window mask file (NONE):
B. For row 2, LEG, order = 1
unix% pset mkgarf order=1 unix% pset mkgarf outfile=1801_1_LEG_garf.fits unix% mkgarf Aspect Histogram File (include extension) (asphist.fits[ASPHIST]): Output File Name (1801_1_LEG_garf.fits): Enter Grating order (1): Source X Pixel (16500.17968750): Source Y Pixel (16366.7568359375): Energy grid spec (grid(rmf.fits[cols ENERG_LO,ENERG_HI])): Name of fits file with obs info (include extension) (hrcf01801N005_evt2.fits[EVENTS]): NONE or Name of fits file with order sorting info (NONE): Detector Name (HRC-I): Enter Grating Arm (HEG|MEG|LEG) (LEG): NONE, or name of ACIS window mask file (NONE):
The content of the parameter file may be checked using plist mkgarf.
Summary
The thread is now complete; the grating ARFs for this dataset are
1801_-1_LEG_garf.fits and 1801_1_LEG_garf.fits. Since this source
is at the aimpoint/on-axis, the two garfs are nearly identical;
this plot shows the +1 order plotted on
top of the -1 order. This is normal and is due to the fact
that the detector is symmetric, flat, and has no holes or
filter boundaries. Also, the HRC-I QEU file is fairly
uniform. Off-axis observations will not have such a high
degree of similarity between the -1 and +1 orders.
Parameters for /home/username/cxcds_param/asphist.par
#--------------------------------------------------------------------------
#
# Parameter file for the ASPECT HISTOGRAM Tool
#
#--------------------------------------------------------------------------
infile = pcadf082337011N003_asol1.fits Aspect Solution List Files
outfile = asphist.fits Aspect Histogram Output File
evtfile = hrcf01801N005_evt2.fits[chip_id=0] Event List Files
dtffile = hrcf01801_000N005_dtf1.fits 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)
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Parameters for /home/username/cxcds_param/mkgarf.par
asphistfile = asphist.fits[ASPHIST] Aspect Histogram File (include extension)
outfile = 1801_1_LEG_garf.fits Output File Name
order = 1 Enter Grating order
sourcepixelx = 16511.48046875 Source X Pixel
sourcepixely = 16367.2802734375 Source Y Pixel
engrid = grid(rmf.fits[cols ENERG_LO,ENERG_HI]) Energy grid spec
obsfile = hrcf01801N005_evt2.fits[EVENTS] Name of fits file with obs info (include extension)
#engrid,f,a,"0.3:10:0.1",,,"Energy grid spec"
#engrid,f,a,"grid(rmf.fits[cols ENERG_LO,ENERG_HI])",,,"Energy grid spec"
osipfile = NONE NONE or Name of fits file with order sorting info
maskfile = NONE NONE, or name of ACIS window mask file
detsubsys = HRC-I Detector Name
grating_arm = LEG Enter Grating Arm
pbkfile = NONE, or the name of the parameter block file
(mirror = hrma) Mirror Name
(dafile = CALDB) NONE, CALDB, or name of ACIS dead-area calibration file
(geompar = geom) Parameter file for Pixlib Geometry files
(verbose = 0) Verbosity
(clobber = no) Overwrite existing files?
(mode = ql) Enter mode for parameter file.
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History
| 22 Dec 2004 | updated for CIAO 3.2: minor changes to parameter files; canned gARFs are no longer available in the CALDB, removed "Choosing an RMF" section |
| 20 Jun 2005 | CIAO 3.2.2 patch: change to asphist parameter file |
| 06 Dec 2005 | updated for CIAO 3.3: new asphist tool syntax (the GTI filter is associated with the event file instead of the aspect solution file) |
| 01 Dec 2006 | updated for CIAO 3.4: CIAO version in warning; ChIPS version; parameter file updates for mkgarf |
| 23 Jan 2008 | updated for CIAO 4.0: parameter file update for mkgarf (obsfile parameter is set to event file instead of aspect histogram file); updated ChIPS syntax; removed outdated calibration updates; filenames and screen output updated for reprocessed data (version N005 files) |
