Density-dependent He-like line models for ISIS

ISIS-users:
       
The He-like triplet lines which occur in the X-ray band from 5-42A are
powerful diagnostics of density or photoexcitation. The APED
(Astrophysical Plasma Emission Database), however, only contains
emissivities for low density. To use triplet lines as a density
diagnostic, one method is to fit the line strengths and from the ratio
of the forbidden to intercombination line fluxes (f/i), then look up
the implied density from external sources. To provide better support
for more direct fitting and modeling, we have

    * made very general modifications to ISIS to provide
      APED-emissivity modifiers;

    * constructed a database of emissivity modifier coefficients which
      parameterize the density dependence;

    * written an ISIS model to implement the modifier via the
      coefficients table.

The files and further details can be found at

http://space.mit.edu/cxc/analysis/hemodifier/index.html


-- Dave

David Huenemoerder  617-253-4283 (o); -253-8084 (f);
MIT Kavli Institute for Astrophysics and Space Research
70 Vassar St., NE80-6065,
Cambridge, MA  02139
[Admin. Asst.: Elaine Tirrell, 617-253-7480, egt_at_email.domain.hidden
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