6533b882fe1ef96bd12dacee

RESEARCH PRODUCT

HAWC Gamma-Ray survey, AGNs at TeV photon energies

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The High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory continuously detects TeV photons and particles within its large field of view, accumulating every day a deeper exposure of two-thirds of the sky. We analyzed 1523days of HAWC live data acquired over four and a half years, in a follow-up analysis of 138 nearby (z<0.3) active galactic nuclei from the Third Catalog of Hard Fermi-LAT sources culminating within 40{deg} of the zenith at Sierra Negra, the HAWC site. This search for persistent TeV emission used a maximum- likelihood analysis assuming intrinsic power-law spectra attenuated by pair production of gamma-ray photons with the extragalactic background light. HAWC clearly detects persistent emission from Mkn421 and Mkn501, the two brightest blazars in the TeV sky, at 65{sigma} and 17{sigma} level, respectively. Marginal evidence, just above the 3{sigma} level, was found for three other known very high-energy emitters: the radio galaxy M87 and the BL Lac objects VERJ0521+211 and 1ES1215+303, the latter two at z~0.1. We find a 4.2{sigma} evidence for collective emission from the set of 30 previously reported very high-energy sources, with Mkn421 and Mkn501 excluded. Upper limits are presented for the sample under the power-law assumption and in the predefined (0.5-2.0), (2.0-8.0), and (8.0-32.0) TeV energy intervals. Cone search capability for table J/ApJ/907/67/table3 (HAWC power-law fits and significances for the revised 136 AGNs from the 3FHL catalog)