Observation of Gamma-Ray Emission from the Galaxy M87 above 250 GeV with VERITAS

The multiwavelength observation of the nearby radio galaxy M87 provides a unique opportunity to study in detail processes occurring in active galactic nuclei from radio waves to TeV -rays. Here we report the detection of -ray emission above 250 GeV from M87 in spring 2007 with the VERITAS atmospheri...

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Published in:The Astrophysical journal 2008-05, Vol.679 (1), p.397-403
Main Authors: Acciari, V. A, Beilicke, M, Blaylock, G, Bradbury, S. M, Buckley, J. H, Bugaev, V, Butt, Y, Celik, O, Cesarini, A, Ciupik, L, Cogan, P, Colin, P, Cui, W, Daniel, M. K, Duke, C, Ergin, T, Falcone, A. D, Fegan, S. J, Finley, J. P, Finnegan, G, Fortin, P, Fortson, L. F, Gibbs, K, Gillanders, G. H, Grube, J, Guenette, R, Gyuk, G, Hanna, D, Hays, E, Holder, J, Horan, D, Hughes, S. B, Hui, M. C, Humensky, T. B, Imran, A, Kaaret, P, Kertzman, M, Kieda, D. B, Kildea, J, Konopelko, A, Krawczynski, H, Krennrich, F, Lang, M. J, LeBohec, S, Lee, K, Maier, G, McCann, A, McCutcheon, M, Millis, J, Moriarty, P, Mukherjee, R, Nagai, T, Ong, R. A, Pandel, D, Perkins, J. S, Pohl, M, Quinn, J, Ragan, K, Reynolds, P. T, Rose, H. J, Schroedter, M, Sembroski, G. H, Smith, A. W, Steele, D, Swordy, S. P, Syson, A, Toner, J. A, Valcarcel, L, Vassiliev, V. V, Wakely, S. P, Ward, J. E, Weekes, T. C, Weinstein, A, White, R. J, Williams, D. A, Wissel, S. A, Wood, M. D, Zitzer, B
Format: Article
Language:English
Subjects:
Astronomy
Earth, ocean, space
Exact sciences and technology
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Summary:The multiwavelength observation of the nearby radio galaxy M87 provides a unique opportunity to study in detail processes occurring in active galactic nuclei from radio waves to TeV -rays. Here we report the detection of -ray emission above 250 GeV from M87 in spring 2007 with the VERITAS atmospheric Cerenkov telescope array and discuss its correlation with the X-ray emission. The -ray emission is measured to be pointlike with an intrinsic source radius less than 4.5 super([image] ). The differential energy spectrum is fitted well by a power-law function: [image] m super(-2) s super(-1) TeV super(-1). We show strong evidence for a year-scale correlation between the -ray flux reported by TeV experiments and the X-ray emission measured by the ASM RXTE observatory, and discuss the possible short-timescale variability. These results imply that the -ray emission from M87 is more likely associated with the core of the galaxy than with other bright X-ray features in the jet.
ISSN:0004-637X
1538-4357
DOI:10.1086/587458