Swift-XRT is an X-ray instrument that explores the soft X-ray band (from 0.1-10 keV). Detailed information and step-by-step analysis threads can be found here. Note that all the info detailed below are taken from the same website.
Swift XRT Analysis Threads
Before you get started with XRT analysis, you need to install the necessary software. Therefore, please go ahead and install HEASOFT. Select Source Code (and pick your operating system) and Swift (all relevant packages will be selected for you). Then you want the XRT calibration files (CALDB, and please make sure update them every 6 months or so).
NOTE 1: If you already know that you are going to use other X-ray satellites listed in the website, do yourself a favor and select them already from the list. Otherwise you will need to reinstall HEASOFT from stratch next time.
NOTE 2: Beware, you are surely going to struggle through this process. But once you’ve done it once, broke your computer, cried to your advisor, and wondered if it’s really worth it, you will know how to do this for the rest of your carreer.
cd /home/lea/Project/Tutorial/Mrk_421/Data/XRT/
Generic:
xrtpipeline indir=obsnumber outdir=./out(or whatever name you choose for the output folder) steminputs=swobsnumber srcra=OBJECT srcdec=OBJECT
For this example:xrtpipeline indir=00030352011/ outdir=./xrtout_00030352011 steminputs=sw00030352011 srcra=OBJECT srcdec=OBJECT
ls
if you Terminal should be listed) that contains the first level filter data. Now, enter this directory:Generic:
cd out(or whatever name you choose for the output folder)
For this example:cd xrtout_00030352011/
xselect
Enter session name >[xsel8479]
(hit ENTER)
read events swobsid
(for this example: read events sw00030352011)
Reset the mission? > [yes]
(hit ENTER)
extract image
plot image
(this will open the image in ds9. Select a circle region around your source of few arcsec (10-15”) and name it source.reg. Then select an annulus background centered on your source and save it as bkg.reg. Close ds9 and go back to your terminal.)
filter region src.reg
extract spectrum
save spectrum src.pha
clear region
filter region bkg.reg
extract spectrum
save spectrum bkg.pha
clear region
exit
no
Generic:
xrtmkarf expofile=swobsidxpcw2po_ex.img phafile=src.pha srcx=-1 srcy=-1 psfflag=yes outfile=out.arf(or whatever name you choose)
For this example:xrtmkarf expofile=sw00030352011xpcw2po_ex.img phafile=src.pha srcx=-1 srcy=-1 psfflag=yes outfile=xrtout.arf
Generic: ` grppha infile=’src.pha’ outfile=’reb15.pha(or whatever name you choose)’ comm=’chkey ancrfile out.arf(or whatever name you chose)&chkey backfile bkg.pha&chkey respfile /savedpathtofile/swxpc0to12s6_20130101v014.rmf&group min 15&exit’
<br> For this example:
grppha infile=’src.pha’ outfile=’reb15_xrt.pha’ comm=’chkey ancrfile xrtout.arf&chkey backfile bkg.pha&chkey respfile /home/lea/Software/caldb/data/swift/xrt/cpf/rmf/swxpc0to12s6_20130101v014.rmf&group min 15&exit’`
NOTE: like before if you simply type grppha in your terminal, few prompts will show up and you can insert the same information as listed above one by one. It is important you remember to add to your .pha file the missing information about where to find the background file spectrum (chkey backfile), the ancillarey response file (chkey ancrfile) AND the instrument response file (chkey respfile).