Define Spectrum. Choices and formats are similar to those used by XSPEC and are given in Section 3. Note that numerical problems can arise if the radiation field is zero throughout a significant energy range, because then the photoionization rates for some ions may be zero, and these appear in the denominator of the equations for the ionization balance. If your input spectrum is not one of the internally supported models, enter `file' to specify a custom spectrum in a text file using the next two parameters.

Tim Kallman 2015-07-28