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.
| Original language | English (Ireland) |
|---|---|
| Number of pages | 7 |
| Journal | Astrophysical Journal |
| Volume | 679 |
| Publication status | Published - 1 May 2008 |
Authors (Note for portal: view the doc link for the full list of authors)
- Authors
- Acciari, VA,Beilicke, M,Blaylock, G,Bradbury, SM,Buckley, JH,Bugaev, V,Butt, Y,Celik, O,Cesarini, A,Ciupik, L,Cogan, P,Colin, P,Cui, W,Daniel, MK,Duke, C,Ergin, T,Falcone, AD,Fegan, SJ,Finley, JP,Finnegan, G,Fortin, P,Fortson, LF,Gibbs, K,Gillanders, GH,Grube, J,Guenette, R,Gyuk, G,Hanna, D,Hays, E,Holder, J,Horan, D,Hughes, SB,Hui, MC,Humensky, TB,Imran, A,Kaaret, P,Kertzman, M,Kieda, DB,Kildea, J,Konopelko, A,Krawczynski, H,Krennrich, F,Lang, MJ,LeBohec, S,Lee, K,Maier, G,McCann, A,McCutcheon, M,Millis, J,Moriarty, P,Mukherjee, R,Nagai, T,Ong, RA,Pandel, D,Perkins, JS,Pohl, M,Quinn, J,Ragan, K,Reynolds, PT,Rose, HJ,Schroedter, M,Sembroski, GH,Smith, AW,Steele, D,Swordy, SP,Syson, A,Toner, JA,Valcarcel, L,Vassiliev, VV,Wakely, SP,Ward, JE,Weekes, TC,Weinstein, A,White, RJ,Williams, DA,Wi