First detections from VLITE-FAST: a 350-MHz commensal system for detecting and localizing fast radio transients with the JVLA

VLITE-Fast is an experiment searching for fast (<2s) radio transients with the National Radio Astronomy Observatory’s Jansky Very Large Array (VLA). Observing commensally with primary VLA science operations, the 300-364 MHz VLA Low-band Ionosphere and Transient Experiment (VLITE) system has a relatively large field-of-view and accumulates over 6000 hours per year on sky with round-the-clock observing. VLITE-Fast runs in parallel to VLITE and forms an incoherent sum of the VLITE data streams from each antenna, plumbs it for short, dispersed pulses, and applies a machine learning classifier to reject terrestrial interference. This real-time search allows pulses consistent with an astrophysical origin to trigger a dump of buffered baseband voltages, which can be coherently analyzed off-line for improved S/N and localization of the transient. The primary science case for VLITE-Fast is the identification of fast radio burst (FRB) host galaxies, which is easily attained with the localization precision of the VLA in its longer baseline A- and B-configurations (<10"). After a long development and commissioning phase, VLITE-Fast is now operating close to design capability and is expected to detect and localize roughly 1 FRB per month, though rates are still uncertain. An analysis of archived incoherent data from early 2020 revealed what is likely the first FRB detected by VLITE-Fast. In this work, we give a brief overview of the VLITE-Fast system and provide details of the current observational status and results, including the large volume of data searched and the FRB candidate.

Work on VLITE-Fast at NRL is supported by Office of Naval Research 6.1 funding. Construction and installation of VLITE was supported by the Naval Research Laboratory (NRL) Sustainment Restoration and Maintenance funding. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.