PyFX: Software Correlator for Wide-Field VLBI with CHIME/FRB Outriggers

Recent advances in computer processing power and data storage capabilities have enabled VLBI localizations over the full primary beam of individual antennas and facilitated wide-field approaches to VLBI data analysis. With its large 200 square degree field of view, the Canadian Hydrogen Intensity Mapping Experiment (CHIME) telescope is the world's leading fast radio burst (FRB) detector, and is currently being outfitted with outrigger stations with the goal of precisely localizing a large sample of FRBs to sub-arcsecond precision. Here we describe the algorithms in PyFX, the software VLBI correlator designed for wide-field, transient VLBI with CHIME/FRB outriggers.