Abstract
We report on the detection of a very rapid TeV gamma-ray flare from BL Lacertae on 2011 June 28 with the Very Energetic Radiation Imaging Telescope Array System (VERITAS). The flaring activity was observed during a 34.6 minute exposure, when the integral flux above 200 GeV reached (3.4 + - 0.6) x 10(-6) photons m(-2) s(-1), roughly 125% of the Crab Nebula flux measured by VERITAS. The light curve indicates that the observations missed the rising phase of the flare but covered a significant portion of the decaying phase. The exponential decay time was determined to be 13 + - 4 minutes, making it one of the most rapid gamma-ray flares seen from a TeV blazar. The gamma-ray spectrum of BL Lacertae during the flare was soft, with a photon index of 3.6 + - 0.4, which is in agreement with the measurement made previously by MAGIC in a lower flaring state. Contemporaneous radio observations of the source with the Very Long Baseline Array revealed the emergence of a new, superluminal component from the core around the time of the TeV gamma-ray flare, accompanied by changes in the optical polarization angle. Changes in flux also appear to have occurred at optical, UV, and GeV gamma-ray wavelengths at the time of the flare, although they are difficult to quantify precisely due to sparse coverage. A strong flare was seen at radio wavelengths roughly four months later, which might be related to the gamma-ray flaring activities. We discuss the implications of these multiwavelength results.
| Original language | English (Ireland) |
|---|---|
| Journal | Astrophysical Journal |
| Volume | 762 |
| Publication status | Published - 1 Jan 2013 |
Authors (Note for portal: view the doc link for the full list of authors)
- Authors
- Arlen, T,Aune, T,Beilicke, M,Benbow, W,Bouvier, A,Buckley, JH,Bugaev, V,Cesarini, A,Ciupik, L,Connolly, MP,Cui, W,Dickherber, R,Dumm, J,Errando, M,Falcone, A,Federici, S,Feng, Q,Finley, JP,Finnegan, G,Fortson, L,Furniss, A,Galante, N,Gall, D,Griffin, S,Grube, J,Gyuk, G,Hanna, D,Holder, J,Humensky, TB,Kaaret, P,Karlsson, N,Kertzman, M,Khassen, Y,Kieda, D,Krawczynski, H,Krennrich, F,Maier, G,Moriarty, P,Mukherjee, R,Nelson, T,de Bhroithe, AO,Ong, RA,Orr, M,Park, N,Perkins, JS,Pichel, A,Pohl, M,Prokoph, H,Quinn, J,Ragan, K,Reyes, LC,Reynolds, PT,Roache, E,Saxon, DB,Schroedter, M,Sembroski, GH,Staszak, D,Telezhinsky, I,Tesic, G,Theiling, M,Tsurusaki, K,Varlotta, A,Vincent, S,Wakely, SP,Weekes, TC,Weinstein, A,Welsing, R,Williams, DA,Zitzer, B,Jorstad, SG,MacDonald, NR,Marscher, AP,Smith, PS,W