X-raying the local interstellar medium
Final Report Abstract
The fitting of X-ray spectra provides an accurate way to measure hydrogen-equivalent column density values N(H). First, we have performed a cross-matching between the Chandra and GAIA catalogs in order to create a data sample of sources with distances and N(H). We used a Bayesian approach to perform such cross-matching in order to take into account positional uncertainty, compute probabilities for each possible match (and also no match cases) and consider all combinatorically possible matches. Then, we studied the distribution of the best-fit parameters in order to excluded from our sample those sources with nonphysical values and to select the best-fit model using statistical criteria (i.e. χ2 values). The final product is a catalog of 9200 sources with distances and N(H) measurements. Future work include the creation of a 3D map of hydrogen density distribution, using the Bayesian method developed in Rezaei Kh. et al. (2017), and including lines-of-sight for which there are no initial observations.
