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Reading the data into Xselect

xselect

starts up xselect. First thing you'll see is:

** xselect V1.3 **

> Enter session name >[xsel] session1

The 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 xselect from 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 xselect session 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 session.

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:


next up previous contents
Next: Image Analysis Up: ROSAT Xselect Guide Previous: Introduction   Contents
Michael Arida 2001-09-20