Simulating SIXA Spectra

SIXA spectra can be simulated with the HEASARC XSPEC program. The following dialog illustrates the simulation of the spectrum of a 5 ksec SIXA observation of a Raymond-Smith plasma with an emission integral of 10⁶⁰ cm^-3, temperature of 10^7.5 K, column density of 10²¹ cm^-2, at a distance of 10 kpc.

   !xspec 13:27:26 12-Feb-96
   XSPEC> model raymond wabs
     mo = wabs[2] (raymond[1])
    Input parameter value, delta, min, bot, top, and max values for ...
    Mod parameter  1 of component  1 raymond  kT(keV)
       1.000      1.0000E-02  8.0000E-03  8.0000E-03   64.00       64.00
    2.73
    Mod parameter  2 of component  1 raymond  Abundanc
       1.000     -1.0000E-03      0.          0.       5.000       5.000
    1.0
    Mod parameter  3 of component  1 raymond  Redshift
          0.     -1.0000E-03      0.          0.       2.000       2.000
    0.0
    Mod parameter  4 of component  1 raymond  norm
       1.000      1.0000E-02      0.          0.      1.0000E+24  1.0000E+24
    0.8356
    Mod parameter  5 of component  2 wabs     nH 10^22
       1.000      1.0000E-03      0.          0.      1.0000E+05  1.0000E+06
    0.1
     -------------------------------------------------------------------------
     -------------------------------------------------------------------------
     mo = wabs[2] (raymond[1])
     Model Fit Model   Component     Parameter   Value
     par   par comp
       1    1    1       raymond     kT(keV)    2.73000     +/-      0.
       2    2    1       raymond     Abundanc   1.00000     frozen
       3    3    1       raymond     Redshift        0.     frozen
       4    4    1       raymond     norm      0.835600     +/-      0.
       5    5    2       wabs        nH 10^22  0.100000     +/-      0.
     -------------------------------------------------------------------------
     -------------------------------------------------------------------------
       3 variable fit parameters
   XSPEC> fakeit none
    For fake data, file #  1 needs response file: sixa.rmf
                 ... and ancillary response file : none
   Use counting statistics in creating fake data? (y) y
    Input optional fake file prefix (max 12 chars): appe
    Override default values for file #    1
    Fake data filename (appesixa.fak):
    T, A, Bkg, cornorm ( 1.0000 , 1.0000 , 1.0000 , 0. ): 5000.0,1735.0
    Net count rate (cts/s) for file   1   242.6    +/-  0.2203
    Chi-Squared =      842.6     using  1007 PHA bins.
    Reduced chi-squared =     0.8392
   XSPEC>

A plot of the raw spectrum in the energy range from 0.5 - 10 keV (channels 1 - 500) is shown in Figure 68. The required response matrix, sixa.rmf, may be obtained from the directory /pub/sxg/xspec in the anonymous ftp node sao-ftp.harvard.edu.

XSPEC may be obtained from the software/xanadu directory in the anonymous ftp node legacy.gsfc.nasa.gov.