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S. R. McCandliss (JHU)
The calculation of molecular hydrogen optical depth templates is described. These templates may be used to quickly identify and model molecular hydrogen absorption features in far-UV spectra, such as those obtained by the Far Ultraviolet Spectroscopic Explorer. The templates may be downloaded freely from the URL \verb+ http://www.pha.jhu.edu/~stephan/h2ools2.html+. Individual templates are calculated containing all the Lyman and Werner transitions originating from a single rotational state (J") of the 0th vibrational level (v") of the ground electronic state. Templates are provided with 0.01~Å\ sampling for doppler parameters ranging from 2~\le b \le~20~km~s-1 and rotational states 0~\le J" \le~15. Each is calculated for a fiducial column density of log[N(cm-2)]~=~21 and may be scaled to any column less than this value without loss of accuracy. The transmission function is calculated by taking the template as the base-e exponent. These templates will facilitate the determination of the distribution of molecular hydrogen column density as a function of rotational level. Observationally these distributions are found to deviate from thermal equilibrium due to diverse processes such as, far-UV fluorescence, shock excitation, and formation pumping.
This work has been supported by NASA grants NAG5-5315, NAG5-10403, and NAG5-11456 to the Johns Hopkins University.
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The author(s) of this abstract have provided an email address for comments about the abstract: stephan@pha.jhu.edu
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Bulletin of the American Astronomical Society, 34, #4
© 2002. The American Astronomical Soceity.