Abstract
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 gamma-rays. Here we report the detection of gamma-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 gamma-ray emission is measured to be pointlike with an intrinsic source radius less than 4.5'. The differential energy spectrum is fitted well by a power-law function: d Phi/dE = (7.4 +/- 1.3(stat) +/- 1.5(sys))(E/TeV)((-2.31 +/- 0.17stat +/- 0.2sys)) 10(-9) m(-2) s(-1) TeV-1. We show strong evidence for a year-scale correlation between the gamma-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 gamma-ray emission from M87 is more likely associated with the core of the galaxy than with other bright X-ray features in the jet.
Published in:
Astrophysical Journal 679,1 (2008) 397-403;
Link to original published article:
http://dx.doi.org/10.1086/587458
Keywords
galaxies : individual (M87, NGC 4486, Virgo A);; gamma rays :;; observations;; Astronomy & Astrophysics
Date of Version
January 2008
Recommended Citation
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.; and Zitzer, B., "Observation of gamma-ray emission from the galaxy M87 above 250 GeV with VERITAS" (2008). Department of Physics and Astronomy Faculty Publications. Paper 640.
https://docs.lib.purdue.edu/physics_articles/640