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Simulating HEPC/LEPC Spectra

HEPC/LEPC spectra can be simulated with the HEASARC XSPEC program. The following dialog illustrates the simulation of the spectrum of a 5 ksec HEPC/LEPC observation of a Raymond-Smith plasma with an emission integral of 1060 cm-3, temperature of 107.5 K, column density of 1021 cm-2, at a distance of 10 kpc.

!xspec 13:04:44 21-Mar-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: lepc.rmf
              ... and ancillary response file : none
Use counting statistics in creating fake data? (y)
 Input optional fake file prefix (max 12 chars): 
 Override default values for file #    1
 Fake data filename (lepc.fak):
 T, A, Bkg, cornorm ( 1.0000 , 1.0000 , 1.0000 , 0. ): 5000.0
 Net count rate (cts/s) for file   1   360.3    +/-  0.2684
 Chi-Squared =      141.4     using   128 PHA bins.
 Reduced chi-squared =      1.131
XSPEC> fakeit none
 For fake data, file #  1 needs response file: hepc.rmf
              ... and ancillary response file : none
Use counting statistics in creating fake data? (y)
 Input optional fake file prefix (max 12 chars):
 Override default values for file #    1
 Fake data filename (hepc.fak):
 T, A, Bkg, cornorm ( 1.0000 , 1.0000 , 1.0000 , 0. ): 5000.0
 Net count rate (cts/s) for file   1   83.20    +/-  0.1290
 Chi-Squared =      100.2     using   128 PHA bins.
 Reduced chi-squared =     0.8017
XSPEC>

Plots of the raw spectra are shown in Figure 51 and Figure 52. The required response matrices, lepc.rmf and hepc.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.



Tomas P. Girnius
1999-01-21