xselect. First thing you'll see is:
xselect V1.3 **
> Enter session name >[xsel] session1
xselect program was originally written for the analysis of ASCA
data but use of FITS formats for the ROSAT data
files has made it relatively
easy to adapt the
xselect software to handle ROSAT data.
Session names are used as the first letters of temporary files so that
you can run multiple sessions of
the same directory so long as you give each session a different name.
You can save the
xselect session (you will be asked if you wish to
save the session upon exiting it)
and later start it up again and continue from where you left off:
in the above example, if you had saved an
called 'session1' before, then it will ask you if you wanted
to restore the saved session.
It should be stressed that images, light curves, spectra and events
files extracted are temporary files and will be lost when you exit from
xselect unless you have saved each (using "save spectrum",
"save curve" etc) or unless you save the
xselect initially comes up with the mission set
to ASCA, this and other
xselect defaults will change when
you read in the events file, and
xselect reads the header.
xselect> read events
> Enter the Event file dir > ./
> Enter Event file list > rp100000n00_bas.fits
(the data need not be in the current working directory and you can reset the default data directory using 'set datadir' /whatever/dir at any time)
xselect will display the new defaults and a summary of the datafile you
have read in, the following shows an example of reading an RDF events file:
xselect> read events
/testdata/rp100000n00_bas.fits Got new mission: ROSAT and new instrument: PSPCC > Reset the mission and instrument? >[yes] This is ROSAT Notes: xselect set up for ROSAT Keywords for time and pha are TIME PI Units of time are SECONDS Keywords for images are X Y Setting: IMAGE binning = 15 WMAP binning = 15 Energy Column = PI Energy rebinning = 1 WMAP keywords = DETX DETY Getting Min and Max for Energy Column... Got min and max for PI: 1 500 Number of files read in: 1 ******************** Observation Catalogue ******************** Data Directory is: /testdata/ HK Directory is: /testdata/ INSTRUME OBJECT DATE RA_NOM DEC_NOM ROR_NUM LIVETIME 1 PSPCC XRT/PSPC 11/04/94 .310590 .188E+04 110590 .188E+04
If you are reading in a US Rev0 format dataset then you will see a slightly different output, the differences are in the PI range and in the names of the keywords containing the information shown in the Observation Catalogue.
Getting Min and Max for Energy Column... Got min and max for PI: 0 255 Number of files read in: 1 ******************** Observation Catalogue ******************** Data Directory is: /testdata/ HK Directory is: /testdata/ INSTRUME DATE-OBS XS-RAPT XS-DECPT XS-OBSID XS-LIVTI 1 PSPC 07/10/93 .208E+03 .693E+02 US701424 .962E+04
In some cases xselect cannot fit the information into the formated observation catalog display, and a field of wild cards (*) may result. If this occurs you can allow an unformated display (which may wrap around to 2 lines) by using
xselect> read events filename tdisp=no
Notes & Warnings:
xspec. Also note that the Rev0 data have PI 0-255 but this will not result in a 1 channel offset in your extracted spectrum (
xselectunderstands what to do with these data).
xselectby typing :
and find out the current state of play by :
xselect> show status
to reset things you can reset the instrument, e.g.
xselect> set instrument PSPC
or reset any parameter by itself, e.g.
xselect> set binsize 200
resets the time bin size to 200 seconds for subsequent extracted light curves.
xselect> lparm extract
NAME TYPE PROMPT DEFAULT ===================================================================== continue BOOLEAN > Continue? > no bin_what STRING > Give parameter to be binned > [binsize_t] REAL > Give bin size in seconds > -1.0 [pharebin_t] INTEGER > Temporary Bin size for PHA > -1 [xybinsize_t] INTEGER > Rebinning factor for the image > -1 [phalcut_t] INTEGER > Temporary Lower cutoff for PHA > -1 [phahcut_t] INTEGER > Temporary Upper cutoff for PHA > -1 [exposure] DOUBLE > Threshold exposure value for the lig 0.99 [use_qdp] BOOLEAN > Use QDP light curves? > no
task defaults are then listed (parameter names ending in _t, such as binsize_t, are temporary parameters which can be used if you wish to set a parameter for one run only, and the normal default to be used thereafter. Many of the _t parameters will not be set if you don't normally use them).