Test data for use with pyXsis

The tar-ball contains HEG +/-1 data from two Chandra HETG observations of Mrk 421, downloaded from TGcat (http://tgcat.mit.edu/)

Data reduction process described in Huenemoerder et al. (2011): http://adsabs.harvard.edu/abs/2011AJ....141..129H

This data is used to test the pyXsis (Python X-ray Spectral Interpretation System) library at https://github.com/eblur/pyxsis