Notes on Dealing with Spectral Files

If SourceSpectrumType is set to Mono, the source is assumed monoenergetic with the energy set in the MonoEnergy parameter.

If it is set to XSPEC_File, it is assumed the spectrum is output from XSPEC using the commands

XSPEC> ...define model spectrum...

XSPEC> plot model

XSPEC> iplot

PLT> wdata model.dat

PLT> quit

In this case, the file will have at least 3 columns, Energy (in keV), delta-Energy, and flux (in ph/cm2/s/keV); the first three rows are ignored as they normally contain text.

If SourceSpectrumType is set to Sherpa_File, it is assumed the spectrum file has two columns, Energy (in keV), and Flux (in ph/cm2/s/keV). If you generate the spectrum file some other way than XSPEC or Sherpa, simply output the spectrum in this format (two columns, energy and flux) and simx should be able to read it.

Important Note

SourceSpectrumType only handles the shape of the spectrum, not the normalization. The normalization is set by the SourceFlux command. A common mistake is to carefully create an XSPEC or Sherpa model that fits the data, and forget to calculate the total flux in this spectrum before exiting XSPEC or Sherpa. simx will always remove any normalization present in this file, and renormalize using the requested total flux.