Parallax-based distance calculator v1

The spiral arms of the Milky Way are being accurately located for the first time via trigonometric parallaxes of massive star forming regions with the BeSSeL Survey, using the Very Long Baseline Array and the European VLBI Network, and with the Japanese VERA project. This calculator leverages these results to significantly improve the accuracy and reliability of distance estimates to other sources that are known to follow spiral structure. Using a Bayesian approach, sources are assigned to arms based on their (l,b,v) coordinates with respect to arm signatures seen in CO and HI surveys. A source's kinematic distance, displacement from the plane, and proximity to individual parallax sources are also considered in generating a full distance probability density function. A more detailed description of the methods can be found in Reid, Dame, Menten & Brunthaler 2016, ApJ 823, 77.

The source code including the paper can be downloaded here: Bayesian_distance_v1.0.tar (~5 MB).