Document Type
Article
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 International License.
Disciplines
Astrophysics and Astronomy | External Galaxies | Stars, Interstellar Medium and the Galaxy
Abstract
The intermediate-frequency peaked BL Lacertae (IBL) object 3C 66A is detected during 2007-2008 in VHE (very high energy; E > 100 GeV) γ rays with the VERITAS stereoscopic array of imaging atmospheric Cherenkov telescopes. An excess of 1791 events is detected, corresponding to a significance of 21.2 standard deviations (σ), in these observations (32.8 hr live time). The observed integral flux above 200 GeV is 6% of the Crab Nebula's flux and shows evidence for variability on the timescale of days. The measured energy spectrum is characterized by a soft power law with photon index Γ = 4.1 ± 0.4stat ± 0.6sys. The radio galaxy 3C 66B is excluded as a possible source of the VHE emission.
Recommended Citation
Acciari, V.A., Aliu, E., Arlen, T., Beilicke, M., Benbow, W., Böttcher, M., Bradbury, S.M., Buckley, J.H., Bugaev, V., Butt, Y., Byrum, K., Cannon, A., Celik, O., Cesarini, A., Chow, Y.C., Ciupik, L., Cogan, P., Cui, W., Daniel, M.K., Dickherber, R., Ergin, T., Falcone, A., Fegan, S.J., Finley, J.P., Fortin, P., Fortson, L., Furniss, A., Gall, D., Gibbs, K., Gillanders, G.H., Godambe, S., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Hays, E., Holder, J., Horan, D., Hui, C.M., Humensky, T.B., Imran, A., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Kildea, J., Konopelko, A., Krawczynski, H., Krennrich, F., Lang, M.J., LeBohec, S., Maier, G., McCann, A., McCutcheon, M., Millis, J., Moriarty, P., Mukherjee, R., Nagai, T., Ong, R.A., Otte, A.N., Pandel, D., Perkins, J.S., Petry, D., Pizlo, F., Pohl, M., Quinn, J., Ragan, K., Reyes, L.C., Reynolds, P.T., Roache, E., Rose, H.J., Schroedter, M., Sembroski, G.H., Smith, A.W., Steele, D., Swordy, S.P., Theiling, M., Toner, J.A., Varlotta, A., Vassiliev, V.V., Wagner, R.G., Wakely, S.P., Ward, J.E., Weekes, T.C., Weinstein, A., Williams, D.A., Wissel, S., Wood, M. and Zitzer, B. (2009). VERITAS OBSERVATIONS OF A VERY HIGH ENERGY γ-RAY FLARE FROM THE BLAZAR 3C 66A. The Astrophysical Journal, [online] 693(2), pp.L104–L108. Available at: https://iopscience.iop.org/article/10.1088/0004-637X/693/2/L104 [Accessed 13 Jan. 2020].
Publication Details
Astrophysical Journal Letters