VERITAS observations of the Be/X-ray binary system LS V +44 17 during a major outburst

Abstract

The Be/X-ray binary system LS V +44 17 (RX J0440.9+4431) is a potential member of the rare class of gamma-ray binaries. The system is comprised of a Be star and a neutron star companion with an orbital period of 150 days. In December of 2022, MAXI detected an X-ray outburst from the source, which peaked in early January before declining and then re-brightening. During the second peak, the flux exceeded 1 Crab in the 15-50 keV range, and exhibited a pulsed emission component with a pulse period of 208 seconds. VERITAS observations were conducted close to the peak of the second outburst, from January 24 to January 27, 2023. We report here on the search for very high energy (VHE) gamma-ray emission in these data.