Fermi Gamma-ray Space Telescope

VERITAS Observations of V404 Cyg During Its Historical 2015 Outburst

A. W. Smith

Abstract:

In June 2015, the black hole binary system V404 Cyg erupted in a fantastic display of energetic flares detected by Fermi-GBM, Swift, and INTEGRAL. These flares, reaching >30x the flux of the Crab nebula in the hard X-ray regime have not been seen since the source was in outburst in 1989. This phenomenal activity triggered observations across the electromagnetic spectrum including TeV observations with the VERITAS array of imaging atmospheric Cherenkov telescopes in southern Arizona. In this paper we will present the VERITAS observations of V404 Cyg from June 20-24, during some of its brightest X-ray activity. While these observations resulted in flux upper limits only, these limits can be used to provide constraints on the energetic limit of particle acceleration occurring during the flaring periods.