TY - JOUR
A1 - Abramowski, Attila
A1 - Acero, F.
A1 - Aharonian, Felix
A1 - Akhperjanian, A. G.
A1 - Anton, Gisela
A1 - Balzer, A.
A1 - Barnacka, A.
A1 - de Almeida, U. Barres
A1 - Becherini, Y.
A1 - Becker, J.
A1 - Behera, B.
A1 - Bernloehr, K.
A1 - Birsin, E.
A1 - Biteau, J.
A1 - Bochow, A.
A1 - Boisson, C.
A1 - Bolmont, J.
A1 - Bordas, P.
A1 - Brucker, J.
A1 - Brun, F.
A1 - Brun, P.
A1 - Bulik, T.
A1 - Buesching, I.
A1 - Carrigan, S.
A1 - Casanova, S.
A1 - Cerruti, M.
A1 - Chadwick, P. M.
A1 - Charbonnier, A.
A1 - Chaves, R. C. G.
A1 - Cheesebrough, A.
A1 - Clapson, A. C.
A1 - Coignet, G.
A1 - Cologna, G.
A1 - Conrad, J.
A1 - Dalton, M.
A1 - Daniel, M. K.
A1 - Davids, I. D.
A1 - Degrange, B.
A1 - Deil, C.
A1 - Dickinson, H. J.
A1 - Djannati-Ataï, A.
A1 - Domainko, W.
A1 - Drury, L. O'C.
A1 - Dubus, G.
A1 - Dutson, K.
A1 - Dyks, J.
A1 - Dyrda, M.
A1 - Egberts, K.
A1 - Eger, P.
A1 - Espigat, P.
A1 - Fallon, L.
A1 - Farnier, C.
A1 - Fegan, S.
A1 - Feinstein, F.
A1 - Fernandes, M. V.
A1 - Fiasson, A.
A1 - Fontaine, G.
A1 - Foerster, A.
A1 - Fuessling, M.
A1 - Gallant, Y. A.
A1 - Gast, H.
A1 - Gerard, L.
A1 - Gerbig, D.
A1 - Giebels, B.
A1 - Glicenstein, J. F.
A1 - Glueck, B.
A1 - Goret, P.
A1 - Goering, D.
A1 - Haeffner, S.
A1 - Hague, J. D.
A1 - Hampf, D.
A1 - Hauser, M.
A1 - Heinz, S.
A1 - Heinzelmann, G.
A1 - Henri, G.
A1 - Hermann, G.
A1 - Hinton, J. A.
A1 - Hoffmann, A.
A1 - Hofmann, W.
A1 - Hofverberg, P.
A1 - Holler, M.
A1 - Horns, D.
A1 - Jacholkowska, A.
A1 - de Jager, O. C.
A1 - Jahn, C.
A1 - Jamrozy, M.
A1 - Jung, I.
A1 - Kastendieck, M. A.
A1 - Katarzynski, K.
A1 - Katz, U.
A1 - Kaufmann, S.
A1 - Keogh, D.
A1 - Khangulyan, D.
A1 - Khelifi, B.
A1 - Klochkov, D.
A1 - Kluzniak, W.
A1 - Kneiske, T.
A1 - Komin, Nu.
A1 - Kosack, K.
A1 - Kossakowski, R.
A1 - Laffon, H.
A1 - Lamanna, G.
A1 - Lennarz, D.
A1 - Lohse, T.
A1 - Lopatin, A.
A1 - Lu, C. -C.
A1 - Marandon, V.
A1 - Marcowith, A.
A1 - Masbou, J.
A1 - Maurin, D.
A1 - Maxted, N.
A1 - Mayer, M.
A1 - McComb, T. J. L.
A1 - Medina, M. C.
A1 - Mehault, J.
A1 - Moderski, R.
A1 - Moulin, E.
A1 - Naumann, C. L.
A1 - Naumann-Godo, M.
A1 - de Naurois, M.
A1 - Nedbal, D.
A1 - Nekrassov, D.
A1 - Nguyen, N.
A1 - Nicholas, B.
A1 - Niemiec, J.
A1 - Nolan, S. J.
A1 - Ohm, S.
A1 - Wilhelmi, E. de Ona
A1 - Opitz, B.
A1 - Ostrowski, M.
A1 - Oya, I.
A1 - Panter, M.
A1 - Arribas, M. Paz
A1 - Pedaletti, G.
A1 - Pelletier, G.
A1 - Petrucci, P. -O.
A1 - Pita, S.
A1 - Puehlhofer, G.
A1 - Punch, M.
A1 - Quirrenbach, A.
A1 - Raue, M.
A1 - Rayner, S. M.
A1 - Reimer, A.
A1 - Reimer, O.
A1 - Renaud, M.
A1 - de los Reyes, R.
A1 - Rieger, F.
A1 - Ripken, J.
A1 - Rob, L.
A1 - Rosier-Lees, S.
A1 - Rowell, G.
A1 - Rudak, B.
A1 - Rulten, C. B.
A1 - Ruppel, J.
A1 - Sahakian, V.
A1 - Sanchez, D. A.
A1 - Santangelo, A.
A1 - Schlickeiser, R.
A1 - Schoeck, F. M.
A1 - Schulz, A.
A1 - Schwanke, U.
A1 - Schwarzburg, S.
A1 - Schwemmer, S.
A1 - Sheidaei, F.
A1 - Skilton, J. L.
A1 - Sol, H.
A1 - Spengler, G.
A1 - Stawarz, L.
A1 - Steenkamp, R.
A1 - Stegmann, C.
A1 - Stinzing, F.
A1 - Stycz, K.
A1 - Sushch, I.
A1 - Szostek, A.
A1 - Tavernet, J. -P.
A1 - Terrier, R.
A1 - Tluczykont, M.
A1 - Valerius, K.
A1 - van Eldik, C.
A1 - Vasileiadis, G.
A1 - Venter, C.
A1 - Vialle, J. P.
A1 - Viana, A.
A1 - Vincent, P.
A1 - Voelk, H. J.
A1 - Volpe, F.
A1 - Vorobiov, S.
A1 - Vorster, M.
A1 - Wagner, S. J.
A1 - Ward, M.
A1 - White, R.
A1 - Wierzcholska, A.
A1 - Zacharias, M.
A1 - Zajczyk, A.
A1 - Zdziarski, A. A.
A1 - Zech, A.
A1 - Zechlin, H. -S.
A1 - Aleksic, J.
A1 - Antonelli, L. A.
A1 - Antoranz, P.
A1 - Backes, M.
A1 - Barrio, J. A.
A1 - Bastieri, D.
A1 - Becerra Gonzalez, J.
A1 - Bednarek, W.
A1 - Berdyugin, A.
A1 - Berger, K.
A1 - Bernardini, E.
A1 - Biland, A.
A1 - Blanch, O.
A1 - Bock, R. K.
A1 - Boller, A.
A1 - Bonnoli, G.
A1 - Tridon, D. Borla
A1 - Braun, I.
A1 - Bretz, T.
A1 - Canellas, A.
A1 - Carmona, E.
A1 - Carosi, A.
A1 - Colin, P.
A1 - Colombo, E.
A1 - Contreras, J. L.
A1 - Cortina, J.
A1 - Cossio, L.
A1 - Covino, S.
A1 - Dazzi, F.
A1 - De Angelis, A.
A1 - De Cea del Pozo, E.
A1 - De Lotto, B.
A1 - Delgado Mendez, C.
A1 - Diago Ortega, A.
A1 - Doert, M.
A1 - Dominguez, A.
A1 - Prester, Dijana Dominis
A1 - Dorner, D.
A1 - Doro, M.
A1 - Elsaesser, D.
A1 - Ferenc, D.
A1 - Fonseca, M. V.
A1 - Font, L.
A1 - Fruck, C.
A1 - Garcia Lopez, R. J.
A1 - Garczarczyk, M.
A1 - Garrido, D.
A1 - Giavitto, G.
A1 - Godinovic, N.
A1 - Hadasch, D.
A1 - Haefner, D.
A1 - Herrero, A.
A1 - Hildebrand, D.
A1 - Hoehne-Moench, D.
A1 - Hose, J.
A1 - Hrupec, D.
A1 - Huber, B.
A1 - Jogler, T.
A1 - Klepser, S.
A1 - Kraehenbuehl, T.
A1 - Krause, J.
A1 - La Barbera, A.
A1 - Lelas, D.
A1 - Leonardo, E.
A1 - Lindfors, E.
A1 - Lombardi, S.
A1 - Lopez, M.
A1 - Lorenz, E.
A1 - Makariev, M.
A1 - Maneva, G.
A1 - Mankuzhiyil, N.
A1 - Mannheim, K.
A1 - Maraschi, L.
A1 - Mariotti, M.
A1 - Martinez, M.
A1 - Mazin, D.
A1 - Meucci, M.
A1 - Miranda, J. M.
A1 - Mirzoyan, R.
A1 - Miyamoto, H.
A1 - Moldon, J.
A1 - Moralejo, A.
A1 - Munar, P.
A1 - Nieto, D.
A1 - Nilsson, K.
A1 - Orito, R.
A1 - Oya, I.
A1 - Paneque, D.
A1 - Paoletti, R.
A1 - Pardo, S.
A1 - Paredes, J. M.
A1 - Partini, S.
A1 - Pasanen, M.
A1 - Pauss, F.
A1 - Perez-Torres, M. A.
A1 - Persic, M.
A1 - Peruzzo, L.
A1 - Pilia, M.
A1 - Pochon, J.
A1 - Prada, F.
A1 - Moroni, P. G. Prada
A1 - Prandini, E.
A1 - Puljak, I.
A1 - Reichardt, I.
A1 - Reinthal, R.
A1 - Rhode, W.
A1 - Ribo, M.
A1 - Rico, J.
A1 - Ruegamer, S.
A1 - Saggion, A.
A1 - Saito, K.
A1 - Saito, T. Y.
A1 - Salvati, M.
A1 - Satalecka, K.
A1 - Scalzotto, V.
A1 - Scapin, V.
A1 - Schultz, C.
A1 - Schweizer, T.
A1 - Shayduk, M.
A1 - Shore, S. N.
A1 - Sillanpaa, A.
A1 - Sitarek, J.
A1 - Sobczynska, D.
A1 - Spanier, F.
A1 - Spiro, S.
A1 - Stamerra, A.
A1 - Steinke, B.
A1 - Storz, J.
A1 - Strah, N.
A1 - Suric, T.
A1 - Takalo, L.
A1 - Takami, H.
A1 - Tavecchio, F.
A1 - Temnikov, P.
A1 - Terzic, T.
A1 - Tescaro, D.
A1 - Teshima, M.
A1 - Thom, M.
A1 - Tibolla, O.
A1 - Torres, D. F.
A1 - Treves, A.
A1 - Vankov, H.
A1 - Vogler, P.
A1 - Wagner, R. M.
A1 - Weitzel, Q.
A1 - Zabalza, V.
A1 - Zandanel, F.
A1 - Zanin, R.
A1 - Arlen, T.
A1 - Aune, T.
A1 - Beilicke, M.
A1 - Benbow, W.
A1 - Bouvier, A.
A1 - Bradbury, S. M.
A1 - Buckley, J. H.
A1 - Bugaev, V.
A1 - Byrum, K.
A1 - Cannon, A.
A1 - Cesarini, A.
A1 - Ciupik, L.
A1 - Connolly, M. P.
A1 - Cui, W.
A1 - Dickherber, R.
A1 - Duke, C.
A1 - Errando, M.
A1 - Falcone, A.
A1 - Finley, J. P.
A1 - Finnegan, G.
A1 - Fortson, L.
A1 - Furniss, A.
A1 - Galante, N.
A1 - Gall, D.
A1 - Godambe, S.
A1 - Griffin, S.
A1 - Grube, J.
A1 - Gyuk, G.
A1 - Hanna, D.
A1 - Holder, J.
A1 - Huan, H.
A1 - Hui, C. M.
A1 - Kaaret, P.
A1 - Karlsson, N.
A1 - Kertzman, M.
A1 - Khassen, Y.
A1 - Kieda, D.
A1 - Krawczynski, H.
A1 - Krennrich, F.
A1 - Lang, M. J.
A1 - LeBohec, S.
A1 - Maier, G.
A1 - McArthur, S.
A1 - McCann, A.
A1 - Moriarty, P.
A1 - Mukherjee, R.
A1 - Nunez, P. D.
A1 - Ong, R. A.
A1 - Orr, M.
A1 - Otte, A. N.
A1 - Park, N.
A1 - Perkins, J. S.
A1 - Pichel, A.
A1 - Pohl, Martin
A1 - Prokoph, H.
A1 - Ragan, K.
A1 - Reyes, L. C.
A1 - Reynolds, P. T.
A1 - Roache, E.
A1 - Rose, H. J.
A1 - Ruppel, J.
A1 - Schroedter, M.
A1 - Sembroski, G. H.
A1 - Sentuerk, G. D.
A1 - Telezhinsky, I.
A1 - Tesic, G.
A1 - Theiling, M.
A1 - Thibadeau, S.
A1 - Varlotta, A.
A1 - Vassiliev, V. V.
A1 - Vivier, M.
A1 - Wakely, S. P.
A1 - Weekes, T. C.
A1 - Williams, D. A.
A1 - Zitzer, B.
A1 - de Almeida, U. Barres
A1 - Cara, M.
A1 - Casadio, C.
A1 - Cheung, C. C.
A1 - McConville, W.
A1 - Davies, F.
A1 - Doi, A.
A1 - Giovannini, G.
A1 - Giroletti, M.
A1 - Hada, K.
A1 - Hardee, P.
A1 - Harris, D. E.
A1 - Junor, W.
A1 - Kino, M.
A1 - Lee, N. P.
A1 - Ly, C.
A1 - Madrid, J.
A1 - Massaro, F.
A1 - Mundell, C. G.
A1 - Nagai, H.
A1 - Perlman, E. S.
A1 - Steele, I. A.
A1 - Walker, R. C.
A1 - Wood, D. L.
T1 - The 2010 very high energy gamma-ray flare and 10 years ofmulti-wavelength oservations of M 87
JF - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2 - The giant radio galaxy M 87 with its proximity (16 Mpc), famous jet, and very massive black hole ((3-6) x 10(9) M-circle dot) provides a unique opportunity to investigate the origin of very high energy (VHE; E > 100 GeV) gamma-ray emission generated in relativistic outflows and the surroundings of supermassive black holes. M 87 has been established as a VHE gamma-ray emitter since 2006. The VHE gamma-ray emission displays strong variability on timescales as short as a day. In this paper, results from a joint VHE monitoring campaign on M 87 by the MAGIC and VERITAS instruments in 2010 are reported. During the campaign, a flare at VHE was detected triggering further observations at VHE (H.E.S.S.), X-rays (Chandra), and radio (43 GHz Very Long Baseline Array, VLBA). The excellent sampling of the VHE gamma-ray light curve enables one to derive a precise temporal characterization of the flare: the single, isolated flare is well described by a two-sided exponential function with significantly different flux rise and decay times of tau(rise)(d) = (1.69 +/- 0.30) days and tau(decay)(d) = (0.611 +/- 0.080) days, respectively. While the overall variability pattern of the 2010 flare appears somewhat different from that of previous VHE flares in 2005 and 2008, they share very similar timescales (similar to day), peak fluxes (Phi(>0.35 TeV) similar or equal to (1-3) x 10(-11) photons cm(-2) s(-1)), and VHE spectra. VLBA radio observations of 43 GHz of the inner jet regions indicate no enhanced flux in 2010 in contrast to observations in 2008, where an increase of the radio flux of the innermost core regions coincided with a VHE flare. On the other hand, Chandra X-ray observations taken similar to 3 days after the peak of the VHE gamma-ray emission reveal an enhanced flux from the core (flux increased by factor similar to 2; variability timescale <2 days). The long-term (2001-2010) multi-wavelength (MWL) light curve of M 87, spanning from radio to VHE and including data from Hubble Space Telescope, Liverpool Telescope, Very Large Array, and European VLBI Network, is used to further investigate the origin of the VHE gamma-ray emission. No unique, common MWL signature of the three VHE flares has been identified. In the outer kiloparsec jet region, in particular in HST-1, no enhanced MWL activity was detected in 2008 and 2010, disfavoring it as the origin of the VHE flares during these years. Shortly after two of the three flares (2008 and 2010), the X-ray core was observed to be at a higher flux level than its characteristic range (determined from more than 60 monitoring observations: 2002-2009). In 2005, the strong flux dominance of HST-1 could have suppressed the detection of such a feature. Published models for VHE gamma-ray emission from M 87 are reviewed in the light of the new data.
KW - galaxies: active
KW - galaxies: individual (M 87)
KW - galaxies: jets
KW - galaxies: nuclei
KW - gamma rays: galaxies
KW - radiation mechanisms: non-thermal
Y1 - 2012
U6 - http://dx.doi.org/10.1088/0004-637X/746/2/151
SN - 0004-637X (print)
VL - 746
IS - 2
PB - IOP Publ. Ltd.
CY - Bristol
ER -
TY - JOUR
A1 - Aliu, E.
A1 - Archambault, S.
A1 - Arlen, T.
A1 - Aune, T.
A1 - Beilicke, M.
A1 - Benbow, W.
A1 - Bouvier, A.
A1 - Bradbury, S. M.
A1 - Buckley, J. H.
A1 - Bugaev, V.
A1 - Byrum, K.
A1 - Cannon, A.
A1 - Cesarini, A.
A1 - Ciupik, L.
A1 - Collins-Hughes, E.
A1 - Connolly, M. P.
A1 - Cui, W.
A1 - Decerprit, G.
A1 - Dickherber, R.
A1 - Duke, C.
A1 - Dumm, J.
A1 - Dwarkadas, V. V.
A1 - Errando, M.
A1 - Falcone, A.
A1 - Feng, Q.
A1 - Finley, J. P.
A1 - Finnegan, G.
A1 - Fortson, L.
A1 - Furniss, A.
A1 - Galante, N.
A1 - Gall, D.
A1 - Godambe, S.
A1 - Griffin, S.
A1 - Grube, J.
A1 - Gyuk, G.
A1 - Hanna, D.
A1 - Holder, J.
A1 - Huan, H.
A1 - Hughes, G.
A1 - Humensky, T. B.
A1 - Kaaret, P.
A1 - Karlsson, N.
A1 - Kertzman, M.
A1 - Khassen, Y.
A1 - Kieda, D.
A1 - Krawczynski, H.
A1 - Krennrich, F.
A1 - Lang, M. J.
A1 - Lee, K.
A1 - Maier, G.
A1 - Majumdar, P.
A1 - McArthur, S.
A1 - McCann, A.
A1 - Millis, J.
A1 - Moriarty, P.
A1 - Mukherjee, R.
A1 - Nunez, P. D.
A1 - Ong, R. A.
A1 - Orr, M.
A1 - Otte, A. N.
A1 - Pandel, D.
A1 - Park, N.
A1 - Perkins, J. S.
A1 - Pohl, M.
A1 - Prokoph, H.
A1 - Quinn, J.
A1 - Ragan, K.
A1 - Reyes, L. C.
A1 - Reynolds, P. T.
A1 - Roache, E.
A1 - Rose, H. J.
A1 - Ruppel, J.
A1 - Saxon, D. B.
A1 - Schroedter, M.
A1 - Sembroski, G. H.
A1 - Skole, C.
A1 - Smith, A. W.
A1 - Staszak, D.
A1 - Telezhinsky, I.
A1 - Tesic, G.
A1 - Theiling, M.
A1 - Thibadeau, S.
A1 - Tsurusaki, K.
A1 - Tyler, J.
A1 - Varlotta, A.
A1 - Vincent, S.
A1 - Vivier, M.
A1 - Wakely, S. P.
A1 - Ward, J. E.
A1 - Weekes, T. C.
A1 - Weinstein, A.
A1 - Weisgarber, T.
A1 - Welsing, R.
A1 - Williams, D. A.
A1 - Zitzer, B.
T1 - Veritas observations of the nova in V407 CYGNI
JF - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2 - We report on very high energy (E > 100 GeV) gamma-ray observations of V407 Cygni, a symbiotic binary that underwent a nova outburst producing 0.1-10 GeV gamma rays during 2010 March 10-26. Observations were made with the Very Energetic Radiation Imaging Telescope Array System during 2010 March 19-26 at relatively large zenith angles due to the position of V407 Cyg. An improved reconstruction technique for large zenith angle observations is presented and used to analyze the data. We do not detect V407 Cygni and place a differential upper limit on the flux at 1.6 TeV of 2.3 x 10(-12) erg cm(-2) s(-1) (at the 95% confidence level). When considered jointly with data from Fermi-LAT, this result places limits on the acceleration of very high energy particles in the nova.
KW - gamma rays: general
KW - novae, cataclysmic variables
KW - white dwarfs
Y1 - 2012
U6 - http://dx.doi.org/10.1088/0004-637X/754/1/77
SN - 0004-637X (print)
VL - 754
IS - 1
PB - IOP Publ. Ltd.
CY - Bristol
ER -
TY - JOUR
A1 - Arlen, T.
A1 - Aune, T.
A1 - Beilicke, M.
A1 - Benbow, W.
A1 - Bouvier, A.
A1 - Buckley, J. H.
A1 - Bugaev, V.
A1 - Byrum, K.
A1 - Cannon, A.
A1 - Cesarini, A.
A1 - Ciupik, L.
A1 - Collins-Hughes, E.
A1 - Connolly, M. P.
A1 - Cui, W.
A1 - Dickherber, R.
A1 - Dumm, J.
A1 - Falcone, A.
A1 - Federici, S.
A1 - Feng, Q.
A1 - Finley, J. P.
A1 - Finnegan, G.
A1 - Fortson, L.
A1 - Furniss, A.
A1 - Galante, N.
A1 - Gall, D.
A1 - Godambe, S.
A1 - Griffin, S.
A1 - Grube, J.
A1 - Gyuk, G.
A1 - Holder, J.
A1 - Huan, H.
A1 - Hughes, G.
A1 - Humensky, T. B.
A1 - Imran, A.
A1 - Kaaret, P.
A1 - Karlsson, N.
A1 - Kertzman, M.
A1 - Khassen, Y.
A1 - Kieda, D.
A1 - Krawczynski, H.
A1 - Krennrich, F.
A1 - Lee, K.
A1 - Madhavan, A. S.
A1 - Maier, G.
A1 - Majumdar, P.
A1 - McArthur, S.
A1 - McCann, A.
A1 - Moriarty, P.
A1 - Mukherjee, R.
A1 - Nelson, T.
A1 - de Bhroithe, A. O'Faolain
A1 - Ong, R. A.
A1 - Orr, M.
A1 - Otte, A. N.
A1 - Park, N.
A1 - Perkins, J. S.
A1 - Pohl, Martin
A1 - Prokoph, H.
A1 - Quinn, J.
A1 - Ragan, K.
A1 - Reyes, L. C.
A1 - Reynolds, P. T.
A1 - Roache, E.
A1 - Ruppel, J.
A1 - Saxon, D. B.
A1 - Schroedter, M.
A1 - Sembroski, G. H.
A1 - Skole, C.
A1 - Smith, A. W.
A1 - Telezhinsky, I.
A1 - Tesic, G.
A1 - Theiling, M.
A1 - Thibadeau, S.
A1 - Tsurusaki, K.
A1 - Varlotta, A.
A1 - Vivier, M.
A1 - Wakely, S. P.
A1 - Ward, J. E.
A1 - Weinstein, A.
A1 - Welsing, R.
A1 - Williams, D. A.
A1 - Zitzer, B.
A1 - Pfrommer, C.
A1 - Pinzke, A.
T1 - Constraints on cosmic rays, magnetic fields, and dark matter fromgamma-ray observations of the coma cluster of galaxies with veritas and fermi
JF - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2 - Observations of radio halos and relics in galaxy clusters indicate efficient electron acceleration. Protons should likewise be accelerated and, on account of weak energy losses, can accumulate, suggesting that clusters may also be sources of very high energy (VHE; E > 100 GeV) gamma-ray emission. We report here on VHE gamma-ray observations of the Coma galaxy cluster with the VERITAS array of imaging Cerenkov telescopes, with complementing Fermi Large Area Telescope observations at GeV energies. No significant gamma-ray emission from the Coma Cluster was detected. Integral flux upper limits at the 99% confidence level were measured to be on the order of (2-5) x 10(-8) photonsm(-2) s(-1) (VERITAS, >220 GeV) and similar to 2 x 10(-6) photonsm(-2) s(-1) (Fermi, 1-3GeV), respectively. We use the gamma-ray upper limits to constrain cosmic rays (CRs) and magnetic fields in Coma. Using an analytical approach, the CR-to-thermal pressure ratio is constrained to be < 16% from VERITAS data and <1.7% from Fermi data (averaged within the virial radius). These upper limits are starting to constrain the CR physics in self-consistent cosmological cluster simulations and cap the maximum CR acceleration efficiency at structure formation shocks to be <50%. Alternatively, this may argue for non-negligible CR transport processes such as CR streaming and diffusion into the outer cluster regions. Assuming that the radio-emitting electrons of the Coma halo result from hadronic CR interactions, the observations imply a lower limit on the central magnetic field in Coma of similar to(2-5.5) mu G, depending on the radial magnetic field profile and on the gamma-ray spectral index. Since these values are below those inferred by Faraday rotation measurements in Coma (for most of the parameter space), this renders the hadronic model a very plausible explanation of the Coma radio halo. Finally, since galaxy clusters are dark matter (DM) dominated, the VERITAS upper limits have been used to place constraints on the thermally averaged product of the total self-annihilation cross section and the relative velocity of the DM particles, .
KW - cosmic rays
KW - dark matter
KW - galaxies: clusters: general
KW - galaxies: clusters: individual (Coma (ACO 1656))
KW - gamma rays: galaxies: clusters
KW - magnetic fields
Y1 - 2012
U6 - http://dx.doi.org/10.1088/0004-637X/757/2/123
SN - 0004-637X (print)
VL - 757
IS - 2
PB - IOP Publ. Ltd.
CY - Bristol
ER -
TY - JOUR
A1 - Aliu, E.
A1 - Archambault, S.
A1 - Arlen, T.
A1 - Aune, T.
A1 - Beilicke, M.
A1 - Benbow, W.
A1 - Boettcher, M.
A1 - Bouvier, A.
A1 - Bugaev, V.
A1 - Cannon, A.
A1 - Cesarini, A.
A1 - Ciupik, L.
A1 - Collins-Hughes, E.
A1 - Connolly, M. P.
A1 - Cui, W.
A1 - Dickherber, R.
A1 - Dumm, J.
A1 - Errando, M.
A1 - Falcone, A.
A1 - Federici, Stefania
A1 - Feng, Q.
A1 - Finley, J. P.
A1 - Finnegan, G.
A1 - Fortson, L.
A1 - Furniss, A.
A1 - Galante, N.
A1 - Gall, D.
A1 - Godambe, S.
A1 - Griffin, S.
A1 - Grube, J.
A1 - Gyuk, G.
A1 - Hanna, D.
A1 - Holder, J.
A1 - Huan, H.
A1 - Hughes, G.
A1 - Hui, C. M.
A1 - Imran, A.
A1 - Jameil, O.
A1 - Kaaret, P.
A1 - Karlsson, N.
A1 - Kertzman, M.
A1 - Kerr, J.
A1 - Khassen, Y.
A1 - Kieda, D.
A1 - Krawczynski, H.
A1 - Krennrich, F.
A1 - Lang, M. J.
A1 - Lee, K.
A1 - Madhavan, A. S.
A1 - Majumdar, P.
A1 - McArthur, S.
A1 - McCann, A.
A1 - Moriarty, P.
A1 - Mukherjee, R.
A1 - Nelson, T.
A1 - de Bhroithe, A. O'Faolain
A1 - Ong, R. A.
A1 - Orr, M.
A1 - Otte, A. N.
A1 - Park, N.
A1 - Perkins, J. S.
A1 - Pichel, A.
A1 - Pohl, Martin
A1 - Quinn, J.
A1 - Ragan, K.
A1 - Reynolds, P. T.
A1 - Roache, E.
A1 - Ruppel, J.
A1 - Saxon, D. B.
A1 - Schroedter, M.
A1 - Sembroski, G. H.
A1 - Sentuerk, G. D.
A1 - Smith, A. W.
A1 - Staszak, D.
A1 - Stroh, M.
A1 - Telezhinsky, I.
A1 - Tesic, G.
A1 - Theiling, M.
A1 - Thibadeau, S.
A1 - Tsurusaki, K.
A1 - Varlotta, A.
A1 - Vassiliev, V. V.
A1 - Vivier, M.
A1 - Wakely, S. P.
A1 - Ward, J. E.
A1 - Weinstein, A.
A1 - Welsing, R.
A1 - Williams, D. A.
A1 - Zitzer, B.
T1 - Multiwavelength observations of the AGN 1ES 0414+009 with veritas, FERMI-LAT, SWIFT-XRT, AND MDM
JF - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2 - We present observations of the BL Lac object 1ES 0414+009 in the >200 GeV gamma-ray band by the VERITAS array of Cherenkov telescopes. 1ES 0414+009 was observed by VERITAS between 2008 January and 2011 February, resulting in 56.2 hr of good quality pointed observations. These observations resulted in a detection of 822 events from the source corresponding to a statistical significance of 6.4 standard deviations (6.4 sigma) above the background. The source flux, showing no evidence for variability, is measured as (5.2 +/- 1.1(stat) +/- 2.6(sys)) x 10(-12) photons cm(-2) s(-1) above 200 GeV, equivalent to approximately 2% of the Crab Nebula flux above this energy. The differential photon spectrum from 230 GeV to 850 GeV is well fit by a power law with a photon index of Gamma = 3.4 +/- 0.5(stat) +/- 0.3(sys) and a flux normalization of (1.6 +/- 0.3(stat) +/- 0.8(sys)) x 10(-11) photons cm(-2) s(-1) at 300 GeV. We also present multiwavelength results taken in the optical (MDM), x-ray (Swift-XRT), and GeV (Fermi-LAT) bands and use these results to construct a broadband spectral energy distribution (SED). Modeling of this SED indicates that homogenous one-zone leptonic scenarios are not adequate to describe emission from the system, with a lepto-hadronic model providing a better fit to the data.
KW - BL Lacertae objects: individual (1ES 0414+009, ERJ0416+011)
KW - gamma rays: galaxies
Y1 - 2012
U6 - http://dx.doi.org/10.1088/0004-637X/755/2/118
SN - 0004-637X (print)
VL - 755
IS - 2
PB - IOP Publ. Ltd.
CY - Bristol
ER -
TY - JOUR
A1 - Aliu, E.
A1 - Archambault, S.
A1 - Arlen, T.
A1 - Aune, T.
A1 - Beilicke, M.
A1 - Benbow, W.
A1 - Bouvier, A.
A1 - Bradbury, S. M.
A1 - Buckley, J. H.
A1 - Bugaev, V.
A1 - Byrum, K.
A1 - Cannon, A.
A1 - Cesarini, A.
A1 - Christiansen, J. L.
A1 - Ciupik, L.
A1 - Collins-Hughes, E.
A1 - Connolly, M. P.
A1 - Cui, W.
A1 - Decerprit, G.
A1 - Dickherber, R.
A1 - Dumm, J.
A1 - Errando, M.
A1 - Falcone, A.
A1 - Feng, Q.
A1 - Ferrer, F.
A1 - Finley, J. P.
A1 - Finnegan, G.
A1 - Fortson, L.
A1 - Furniss, A.
A1 - Galante, N.
A1 - Gall, D.
A1 - Godambe, S.
A1 - Griffin, S.
A1 - Grube, J.
A1 - Gyuk, G.
A1 - Hanna, D.
A1 - Holder, J.
A1 - Huan, H.
A1 - Hughes, G.
A1 - Humensky, T. B.
A1 - Kaaret, P.
A1 - Karlsson, N.
A1 - Kertzman, M.
A1 - Khassen, Y.
A1 - Kieda, D.
A1 - Krawczynski, H.
A1 - Krennrich, F.
A1 - Lee, K.
A1 - Madhavan, A. S.
A1 - Maier, G.
A1 - Majumdar, P.
A1 - McArthur, S.
A1 - McCann, A.
A1 - Moriarty, P.
A1 - Mukherjee, R.
A1 - Ong, R. A.
A1 - Orr, M.
A1 - Otte, A. N.
A1 - Park, N.
A1 - Perkins, J. S.
A1 - Pohl, Martin
A1 - Prokoph, H.
A1 - Quinn, J.
A1 - Ragan, K.
A1 - Reyes, L. C.
A1 - Reynolds, P. T.
A1 - Roache, E.
A1 - Rose, H. J.
A1 - Ruppel, J.
A1 - Saxon, D. B.
A1 - Schroedter, M.
A1 - Sembroski, G. H.
A1 - Sentuerk, G. D.
A1 - Skole, C.
A1 - Smith, A. W.
A1 - Staszak, D.
A1 - Telezhinsky, Igor
A1 - Tesic, G.
A1 - Theiling, M.
A1 - Thibadeau, S.
A1 - Tsurusaki, K.
A1 - Varlotta, A.
A1 - Vassiliev, V. V.
A1 - Vincent, S.
A1 - Vivier, M.
A1 - Wagner, R. G.
A1 - Wakely, S. P.
A1 - Ward, J. E.
A1 - Weekes, T. C.
A1 - Weinstein, A.
A1 - Weisgarber, T.
A1 - Williams, D. A.
A1 - Zitzer, B.
T1 - VERITAS deep observations of the dwarf spheroidal galaxy Segue 1
JF - Physical review : D, Particles, fields, gravitation, and cosmology
N2 - The VERITAS array of Cherenkov telescopes has carried out a deep observational program on the nearby dwarf spheroidal galaxy Segue 1. We report on the results of nearly 48 hours of good quality selected data, taken between January 2010 and May 2011. No significant gamma-ray emission is detected at the nominal position of Segue 1, and upper limits on the integrated flux are derived. According to recent studies, Segue 1 is the most dark matter-dominated dwarf spheroidal galaxy currently known. We derive stringent bounds on various annihilating and decaying dark matter particle models. The upper limits on the velocity-weighted annihilation cross-section are (95%) (CL) less than or similar to 10(-23) cm(3) s(-1), improving our limits from previous observations of dwarf spheroidal galaxies by at least a factor of 2 for dark matter particle masses m(chi) greater than or similar to 300 GeV. The lower limits on the decay lifetime are at the level of tau(95%) (CL) greater than or similar to 10(24) s. Finally, we address the interpretation of the cosmic ray lepton anomalies measured by ATIC and PAMELA in terms of dark matter annihilation, and show that the VERITAS observations of Segue 1 disfavor such a scenario.
Y1 - 2012
U6 - http://dx.doi.org/10.1103/PhysRevD.85.062001
SN - 1550-7998 (print)
VL - 85
IS - 6
PB - American Physical Society
CY - College Park
ER -
TY - JOUR
A1 - Aliu, E.
A1 - Archambault, S.
A1 - Arlen, T.
A1 - Aune, T.
A1 - Beilicke, M.
A1 - Benbow, W.
A1 - Bouvier, A.
A1 - Buckley, J. H.
A1 - Bugaev, V.
A1 - Byrum, K.
A1 - Cesarini, A.
A1 - Ciupik, L.
A1 - Collins-Hughes, E.
A1 - Connolly, M. P.
A1 - Cui, W.
A1 - Dickherber, R.
A1 - Duke, C.
A1 - Dumm, J.
A1 - Falcone, A.
A1 - Federici, S.
A1 - Feng, Q.
A1 - Finley, J. P.
A1 - Finnegan, G.
A1 - Fortson, L.
A1 - Furniss, A.
A1 - Galante, N.
A1 - Gall, D.
A1 - Gillanders, G. H.
A1 - Godambe, S.
A1 - Griffin, S.
A1 - Grube, J.
A1 - Gyuk, G.
A1 - Hanna, D.
A1 - Holder, J.
A1 - Huan, H.
A1 - Hughes, G.
A1 - Humensky, T. B.
A1 - Kaaret, P.
A1 - Karlsson, N.
A1 - Khassen, Y.
A1 - Kieda, D.
A1 - Krawczynski, H.
A1 - Krennrich, F.
A1 - Lang, M. J.
A1 - LeBohec, S.
A1 - Lee, K.
A1 - Lyutikov, M.
A1 - Madhavan, A. S.
A1 - Maier, G.
A1 - Majumdar, P.
A1 - McArthur, S.
A1 - McCann, A.
A1 - Moriarty, P.
A1 - Mukherjee, R.
A1 - Nelson, T.
A1 - de Bhroithe, A. O'Faolain
A1 - Ong, R. A.
A1 - Orr, M.
A1 - Otte, A. N.
A1 - Park, N.
A1 - Perkins, J. S.
A1 - Pohl, M.
A1 - Prokoph, H.
A1 - Quinn, J.
A1 - Ragan, K.
A1 - Reyes, L. C.
A1 - Reynolds, P. T.
A1 - Roache, E.
A1 - Saxon, D. B.
A1 - Schrödter, M.
A1 - Sembroski, G. H.
A1 - Sentuerk, G. D.
A1 - Smith, A. W.
A1 - Staszak, D.
A1 - Telezhinsky, I.
A1 - Tesic, G.
A1 - Theiling, M.
A1 - Thibadeau, S.
A1 - Tsurusaki, K.
A1 - Varlotta, A.
A1 - Vincent, S.
A1 - Vivier, M.
A1 - Wagner, R. G.
A1 - Wakely, S. P.
A1 - Weekes, T. C.
A1 - Weinstein, A.
A1 - Welsing, R.
A1 - Williams, D. A.
A1 - Zitzer, B.
A1 - Kondratiev, V.
T1 - SEARCH FOR A CORRELATION BETWEEN VERY-HIGH-ENERGY GAMMA RAYS AND GIANT RADIO PULSES IN THE CRAB PULSAR
JF - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2 - We present the results of a joint observational campaign between the Green Bank radio telescope and the VERITAS gamma-ray telescope, which searched for a correlation between the emission of very-high-energy (VHE) gamma rays (E-gamma > 150 GeV) and giant radio pulses (GRPs) from the Crab pulsar at 8.9 GHz. A total of 15,366 GRPs were recorded during 11.6 hr of simultaneous observations, which were made across four nights in 2008 December and in 2009 November and December. We searched for an enhancement of the pulsed gamma-ray emission within time windows placed around the arrival time of the GRP events. In total, eight different time windows with durations ranging from 0.033 ms to 72 s were positioned at three different locations relative to the GRP to search for enhanced gamma-ray emission which lagged, led, or was concurrent with, the GRP event. Furthermore, we performed separate searches on main pulse GRPs and interpulse GRPs and on the most energetic GRPs in our data sample. No significant enhancement of pulsed VHE emission was found in any of the preformed searches. We set upper limits of 5-10 times the average VHE flux of the Crab pulsar on the flux simultaneous with interpulse GRPs on single-rotation-period timescales. On similar to 8 s timescales around interpulse GRPs, we set an upper limit of 2-3 times the average VHE flux. Within the framework of recent models for pulsed VHE emission from the Crab pulsar, the expected VHE-GRP emission correlations are below the derived limits.
KW - rays: stars
KW - pulsars: individual: B0531+21
Y1 - 2012
U6 - http://dx.doi.org/10.1088/0004-637X/760/2/136
SN - 0004-637X (print)
VL - 760
IS - 2
PB - IOP Publ. Ltd.
CY - Bristol
ER -
TY - JOUR
A1 - Aliu, E.
A1 - Archambault, S.
A1 - Arlen, T.
A1 - Aune, T.
A1 - Beilicke, M.
A1 - Benbow, W.
A1 - Boettcher, M.
A1 - Bouvier, A.
A1 - Buckley, J. H.
A1 - Bugaev, V.
A1 - Cesarini, A.
A1 - Ciupik, L.
A1 - Collins-Hughes, E.
A1 - Connolly, M. P.
A1 - Cui, W.
A1 - Dickherber, R.
A1 - Duke, C.
A1 - Dumm, J.
A1 - Errando, M.
A1 - Falcone, A.
A1 - Federici, Simone
A1 - Feng, Q.
A1 - Finley, J. P.
A1 - Finnegan, G.
A1 - Fortson, L.
A1 - Furniss, A.
A1 - Galante, N.
A1 - Gall, D.
A1 - Godambe, S.
A1 - Griffin, S.
A1 - Grube, J.
A1 - Gyuk, G.
A1 - Hanna, D.
A1 - Holder, J.
A1 - Huan, H.
A1 - Kaaret, P.
A1 - Karlsson, N.
A1 - Khassen, Y.
A1 - Kieda, D.
A1 - Krawczynski, H.
A1 - Krennrich, F.
A1 - Lee, K.
A1 - Madhavan, A. S.
A1 - Maier, G.
A1 - Majumdar, P.
A1 - McArthur, S.
A1 - McCann, A.
A1 - Moriarty, P.
A1 - Mukherjee, R.
A1 - Nelson, T.
A1 - de Bhroithe, A. O'Faolain
A1 - Ong, R. A.
A1 - Orr, M.
A1 - Otte, A. N.
A1 - Park, N.
A1 - Perkins, J. S.
A1 - Pichel, A.
A1 - Pohl, Martin
A1 - Prokoph, H.
A1 - Quinn, J.
A1 - Ragan, K.
A1 - Reyes, L. C.
A1 - Reynolds, P. T.
A1 - Roache, E.
A1 - Saxon, D. B.
A1 - Sembroski, G. H.
A1 - Staszak, D.
A1 - Telezhinsky, Igor
A1 - Tesic, G.
A1 - Theiling, M.
A1 - Thibadeau, S.
A1 - Tsurusaki, K.
A1 - Varlotta, A.
A1 - Vassiliev, V. V.
A1 - Vincent, S.
A1 - Vivier, M.
A1 - Wakely, S. P.
A1 - Weekes, T. C.
A1 - Weinstein, A.
A1 - Welsing, R.
A1 - Williams, D. A.
A1 - Zitzer, B.
A1 - Fortin, P.
A1 - Horan, D.
A1 - Fumagalli, M.
A1 - Kaplan, K.
A1 - Prochaska, J. X.
T1 - Veritas observations of six bright, hard-spectrum fermi-lat blazars
JF - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2 - We report on VERITAS very high energy (VHE; E >= 100 GeV) observations of six blazars selected from the Fermi Large Area Telescope First Source Catalog (1FGL). The gamma-ray emission from 1FGL sources was extrapolated up to the VHE band, taking gamma-ray absorption by the extragalactic background light into account. This allowed the selection of six bright, hard-spectrum blazars that were good candidate TeV emitters. Spectroscopic redshift measurements were attempted with the Keck Telescope for the targets without Sloan Digital Sky Survey spectroscopic data. No VHE emission is detected during the observations of the six sources described here. Corresponding TeV upper limits are presented, along with contemporaneous Fermi observations and non-concurrent Swift UVOT and X-Ray Telescope data. The blazar broadband spectral energy distributions (SEDs) are assembled and modeled with a single-zone synchrotron self-Compton model. The SED built for each of the six blazars shows a synchrotron peak bordering between the intermediate-and high-spectrum-peak classifications, with four of the six resulting in particle-dominated emission regions.
KW - BL Lacertae objects: general
KW - gamma rays: galaxies
Y1 - 2012
U6 - http://dx.doi.org/10.1088/0004-637X/759/2/102
SN - 0004-637X (print)
VL - 759
IS - 2
PB - IOP Publ. Ltd.
CY - Bristol
ER -
TY - JOUR
A1 - Aliu, E.
A1 - Arlen, T.
A1 - Aune, T.
A1 - Beilicke, M.
A1 - Benbow, W.
A1 - Bouvier, A.
A1 - Bradbury, S. M.
A1 - Buckley, J. H.
A1 - Bugaev, V.
A1 - Byrum, K.
A1 - Cannon, A.
A1 - Cesarini, A.
A1 - Ciupik, L.
A1 - Collins-Hughes, E.
A1 - Connolly, M. P.
A1 - Cui, W.
A1 - Dickherber, R.
A1 - Duke, C.
A1 - Errando, M.
A1 - Falcone, A.
A1 - Finley, J. P.
A1 - Finnegan, G.
A1 - Fortson, L.
A1 - Furniss, A.
A1 - Galante, N.
A1 - Gall, D.
A1 - Godambe, S.
A1 - Griffin, S.
A1 - Grube, J.
A1 - Guenette, R.
A1 - Gyuk, G.
A1 - Hanna, D.
A1 - Holder, J.
A1 - Huan, H.
A1 - Hughes, G.
A1 - Hui, C. M.
A1 - Humensky, T. B.
A1 - Imran, A.
A1 - Kaaret, P.
A1 - Karlsson, N.
A1 - Kertzman, M.
A1 - Kieda, D.
A1 - Krawczynski, H.
A1 - Krennrich, F.
A1 - Lang, M. J.
A1 - LeBohec, S.
A1 - Madhavan, A. S.
A1 - Maier, G.
A1 - Majumdar, P.
A1 - McArthur, S.
A1 - McCann, A.
A1 - Moriarty, P.
A1 - Mukherjee, R.
A1 - Nunez, P. D.
A1 - Ong, R. A.
A1 - Orr, M.
A1 - Otte, A. N.
A1 - Park, N.
A1 - Perkins, J. S.
A1 - Pichel, A.
A1 - Pohl, Martin
A1 - Prokoph, H.
A1 - Quinn, J.
A1 - Ragan, K.
A1 - Reyes, L. C.
A1 - Reynolds, P. T.
A1 - Roache, E.
A1 - Rose, H. J.
A1 - Ruppel, J.
A1 - Saxon, D. B.
A1 - Schroedter, M.
A1 - Sembroski, G. H.
A1 - Sentuerk, G. D.
A1 - Skole, C.
A1 - Staszak, D.
A1 - Tesic, G.
A1 - Theiling, M.
A1 - Thibadeau, S.
A1 - Tsurusaki, K.
A1 - Tyler, J.
A1 - Varlotta, A.
A1 - Vassiliev, V. V.
A1 - Vincent, S.
A1 - Vivier, M.
A1 - Wakely, S. P.
A1 - Ward, J. E.
A1 - Weekes, T. C.
A1 - Weinstein, A.
A1 - Weisgarber, T.
A1 - Williams, D. A.
A1 - Zitzer, B.
T1 - Veritas observations of day-scale flaring of M 87 in 2010 April
JF - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2 - VERITAS has been monitoring the very-high-energy (VHE; > 100 GeV) gamma-ray activity of the radio galaxy M87 since 2007. During 2008, flaring activity on a timescale of a few days was observed with a peak flux of (0.70 +/- 0.16) x 10(-11) cm(-2) s(-1) at energies above 350 GeV. In 2010 April, VERITAS detected a flare from M 87 with peak flux of (2.71 +/- 0.68) x 10(-11) cm(-2) s(-1) for E > 350 GeV. The source was observed for six consecutive nights during the flare, resulting in a total of 21 hr of good-quality data. The most rapid flux variation occurred on the trailing edge of the flare with an exponential flux decay time of 0.90(-0.15)(+0.22) days. The shortest detected exponential rise time is three times as long, at 2.87(+1.65)(-0.99) days. The quality of the data sample is such that spectral analysis can be performed for three periods: rising flux, peak flux, and falling flux. The spectra obtained are consistent with power-law forms. The spectral index at the peak of the flare is equal to 2.19 +/- 0.07. There is some indication that the spectrum is softer in the falling phase of the flare than the peak phase, with a confidence level corresponding to 3.6 standard deviations. We discuss the implications of these results for the acceleration and cooling rates of VHE electrons in M 87 and the constraints they provide on the physical size of the emitting region.
KW - galaxies: individual (M 87, VER J1230+123)
KW - gamma rays: galaxies
Y1 - 2012
U6 - http://dx.doi.org/10.1088/0004-637X/746/2/141
SN - 0004-637X (print)
VL - 746
IS - 2
PB - IOP Publ. Ltd.
CY - Bristol
ER -
TY - JOUR
A1 - Aliu, E.
A1 - Archambault, S.
A1 - Arlen, T.
A1 - Aune, T.
A1 - Beilicke, M.
A1 - Benbow, W.
A1 - Boettcher, M.
A1 - Bouvier, A.
A1 - Bradbury, S. M.
A1 - Buckley, J. H.
A1 - Bugaev, V.
A1 - Byrum, K.
A1 - Cannon, A.
A1 - Cesarini, A.
A1 - Ciupik, L.
A1 - Collins-Hughes, E.
A1 - Connolly, M. P.
A1 - Coppi, P.
A1 - Cui, W.
A1 - Decerprit, G.
A1 - Dickherber, R.
A1 - Dumm, J.
A1 - Errando, Manel
A1 - Falcone, A.
A1 - Feng, Q.
A1 - Finley, J. P.
A1 - Finnegan, G.
A1 - Fortson, L.
A1 - Furniss, A.
A1 - Galante, N.
A1 - Gall, D.
A1 - Godambe, S.
A1 - Griffin, S.
A1 - Grube, J.
A1 - Gyuk, G.
A1 - Hanna, D.
A1 - Hawkins, K.
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T1 - Disovery of high-energy and very high energy gamma-ray emission from the blazar RBS 0413
JF - The astrophysical journal : an international review of spectroscopy and astronomical physics
N2 - We report on the discovery of high-energy (HE; E > 0.1 GeV) and very high energy (VHE; E > 100 GeV) gamma-ray emission from the high-frequency-peaked BL Lac object RBS 0413. VERITAS, a ground-based gamma-ray observatory, detected VHE. rays from RBS 0413 with a statistical significance of 5.5 standard deviations (sigma) and a gamma-ray flux of (1.5 +/- 0.6(stat) +/- 0.7(syst)) x 10(-8) photons m(-2) s(-1) (similar to 1% of the Crab Nebula flux) above 250 GeV. The observed spectrum can be described by a power law with a photon index of 3.18 +/- 0.68(stat) +/- 0.30(syst). Contemporaneous observations with the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope detected HE gamma rays from RBS 0413 with a (stat)istical significance of more than 9 sigma, a power-law photon index of 1.57 +/- 0.12(stat-0.12sys')(+0.11) and a gamma-ray flux between 300 MeV and 300 GeV of (1.64 +/- 0.43(stat-0.22sys)(+ 0.31)) x 10(-5) photons m(-2) s(-1). We present the results from Fermi-LAT and VERITAS, including a spectral energy distribution modeling of the gamma-ray, quasi-simultaneous X-ray (Swift-XRT), ultraviolet (Swift-UVOT), and R-band optical (MDM) data. We find that, if conditions close to equipartition are required, both the combined synchrotron self-Compton/external-Compton and the lepto-hadronic models are preferred over a pure synchrotron self-Compton model.
KW - BL Lacertae objects: individual (RBS 0413-VER J0319+187)
KW - gamma rays: galaxies
Y1 - 2012
U6 - http://dx.doi.org/10.1088/0004-637X/750/2/94
SN - 0004-637X (print)
VL - 750
IS - 2
PB - IOP Publ. Ltd.
CY - Bristol
ER -