Absorption due to gas in coronal equilibrium.

An analytic model for calculating absorption spectra from gas which is in coronal equilibrium is available. This model is the coronal analog of the 'warmabs' model. It uses the same xstar atomic database, but uses ionization equilibrium calculated in the absence of a photoionizing flux, assuming a given electron temperature.

Similar to warmabs it has the advantage that it avoids the intrinsic approximations associated with use of tables for absorption with variable abundances treated as multiplicative parameters, and the intrinsic clumsiness of the use of tables. It also allows the use of arbitrary spectral resolution, not limited by the internal xstar spectral resolution. To use it, download the tarfile (this is the same file as for the warmabs model), unzip and untar in your user area, and follow the installation instructions contained in the README. This subroutine is still in the testing phase, so please send reports of bugs and problems.

Note added on 2/29/08: the tar file has been updated for the latest version of xstar including recent iron M-shell UTA calculations.

Keith Arnaud, Lab. for High Energy Astrophysics, NASA/Goddard Space Flight Center

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Last modified: Friday, 29-Feb-2008 15:13:34 EST