htau

A High-Resolution Molecular Hydrogen Optical Depth Template in the Lyman-Werner Absorption Band

Description & Features (planned)

This Python package *will* offer the tool to create and use high-resolution molecular hydrogen optical depth templates in the Lyman-Werner absorption bands. The principles and advantages of such templates for relevant FUV spectroscopy analysis were presented in McCandliss 2003. Despite following the same idea, htau is different in several aspects:

• The package is fully written in Python (instead of IDL) and takes the advantages of existing Python libraries/framework (astropy, linetools, etc.)
• meet open-source standards with modern documentation
• automatically compile HI and H2 atomic/molecular data from online sources (not distributed along with htau)
• offers a command-line interface to efficiently generate templates locally to your specifications (e.g. spectral resolution, sampling of b-values), therefore no need to distribute bulky pre-calculated tables

Note

I wrote a primitive IDL version of htau many years ago, which was an attempt to create similar templates to McCandliss 2003 with more efficient computing methods, finer resolution/b-value sampling, and updated atomic/molecular data. That effort was used in Welty, Xue, & Wong 2012.

TODO

• parse the atomic/molecular data of H2/HD/HI/DI from sources into the linetools.LineList format
• derive tau tables per rotational band on a log(wave)-b grid
• spectrum "maker" (interpolation/gridding/flux-conservation)
• translate calc_igmtau.pro into Python