From 187124303eee7b45be78b8b7b9f93fde4b328dff Mon Sep 17 00:00:00 2001
From: Aaron LI <aaronly.me@outlook.com>
Date: Mon, 6 Mar 2017 16:06:58 +0800
Subject: HOWTO: update local background spectrum
---
doc/HOWTO_chandra_acis_analysis.txt | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)
(limited to 'doc')
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'
--
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