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| author | Aaron LI <aaronly.me@outlook.com> | 2017-03-06 16:06:58 +0800 |
|---|---|---|
| committer | Aaron LI <aaronly.me@outlook.com> | 2017-03-06 16:06:58 +0800 |
| commit | 187124303eee7b45be78b8b7b9f93fde4b328dff (patch) | |
| tree | ba23f2e7385778177fc24cc1739abfa1c3aa922c | |
| parent | 7941e22b66edea6f90fc1a170d0fce76b1befadb (diff) | |
| download | chandra-acis-analysis-187124303eee7b45be78b8b7b9f93fde4b328dff.tar.bz2 | |
HOWTO: update local background spectrum
| -rw-r--r-- | doc/HOWTO_chandra_acis_analysis.txt | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/doc/HOWTO_chandra_acis_analysis.txt b/doc/HOWTO_chandra_acis_analysis.txt index 2dd047b..9935816 100644 --- a/doc/HOWTO_chandra_acis_analysis.txt +++ b/doc/HOWTO_chandra_acis_analysis.txt @@ -24,9 +24,9 @@ Step-by-step guide to analyze ACIS data: extended source as possible as the *local background*, then save to a region file: 'lbkg.reg'. (8) Estimate the total photon counts within the local background region: - $ dmlist "evt2*_clean.fits[sky=region(lbkg.reg)][energy=400:8000]" blocks + $ dmlist "evt2*_clean.fits[sky=region(lbkg.reg)][energy=400:8000]" counts Enlarge the regions if the total photon counts are too small - (e.g., say 2,000). + (e.g., say 3,000). (9) Query the redshift from NED and nH from the HEASARC nH tool (10) $ ciao_bkg_spectra.sh reg=lbkg.reg (11) $ xspec @@ -35,8 +35,16 @@ Step-by-step guide to analyze ACIS data: xspec> cpd /xs xspec> pl l del xspec> @<path>/xspec_bkgcorr.tcl +(??) <TODO> If the background correction does not look good, e.g., the source + is very distant and compact and the emission is very faint, then it is + recommended to just use the *local background*. + Therefore, shrink the above 'lbkg.reg' accordingly and save as + 'localbkg.reg', then extract the local background spectrum: + $ punlearn dmextract + $ dmextract infile="evt2_*_clean.fits[sky=region(localbkg.reg)][bin pi" \ + outfile=localbkg.pi (??) <TODO> Add background spectrum to manifest: - $ manifest.py setpath bkg_spec <bkgcorr_blanksky_lbkg.pi | lbkg.pi> + $ manifest.py setpath bkg_spec <bkgcorr_blanksky_lbkg.pi | localbkg.pi> (12) $ cd ../img $ ln -s ../evt/evt2*_clean.fits . $ ln -s ../bkg/bkgcorr_blanksky_lbkg.pi . # maybe 'lbkg.pi' |