VERITAS detection of the radio galaxy NGC 1275 with elevated very-high-energy gamma-ray emission

ATel #9931; Reshmi Mukherjee (Barnard College) for the VERITAS Collaboration
on 4 Jan 2017; 02:51 UT
Credential Certification: Reshmi Mukherjee (muk@astro.columbia.edu)

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The VERITAS collaboration reports the detection of enhanced gamma-ray activity from a source positionally consistent with the radio galaxy NGC 1275 (z = 0.01756). The VERITAS data were taken on January 2, 2017 UTC (MJD 57755), in response to a flare alert received directly from the MAGIC observing team (also see ATel #9929), resulting in a total of ~2.5 hours (~4:07 UTC to ~6:39 UTC) of data. A preliminary analysis of these data yields a significant detection with the mean flux for the night of (2.03 +/- 0.11) x 10^-10 cm^-2 s^-1 above 170 GeV (corresponding to ~65% of the flux from the Crab Nebula). The VERITAS observations were taken with only three of the array's four telescopes. The fluxes observed by VERITAS and MAGIC are the brightest recorded from this source; the previous record flux was the recently observed flare at ~15%of the Crab Nebula flux reported by both MAGIC (ATel #9689) and VERITAS (ATel #9690). VERITAS will continue to observe NGC 1275 and multiwavelength observations are encouraged. Questions regarding the VERITAS observations should be directed to Reshmi Mukherjee (muk@astro.columbia.edu). VERITAS (Very Energetic Radiation Imaging Telescope Array System) is an array of four atmospheric Cherenkov telescopes, located at the Fred Lawrence Whipple Observatory in southern Arizona, USA, and is most sensitive to gamma rays with energies between ~85 GeV and ~30 TeV (http://veritas.sao.arizona.edu).