@article{ActisAgnettaAharonianetal.2011, author = {Actis, M. and Agnetta, G. and Aharonian, Felix A. and Akhperjanian, A. G. and Aleksic, J. and Aliu, E. and Allan, D. and Allekotte, I. and Antico, F. and Antonelli, L. A. and Antoranz, P. and Aravantinos, A. and Arlen, T. and Arnaldi, H. and Artmann, S. and Asano, K. and Asorey, H. G. and Baehr, J. and Bais, A. and Baixeras, C. and Bajtlik, S. and Balis, D. and Bamba, A. and Barbier, C. and Barcelo, M. and Barnacka, Anna and Barnstedt, J{\"u}rgen and de Almeida, U. Barres and Barrio, J. A. and Basso, S. and Bastieri, D. and Bauer, C. and Becerra Gonzalez, J. and Becherini, Yvonne and Bechtol, K. C. and Becker, J. and Beckmann, Volker and Bednarek, W. and Behera, B. and Beilicke, M. and Belluso, M. and Benallou, M. and Benbow, W. and Berdugo, J. and Berger, K. and Bernardino, T. and Bernl{\"o}hr, K. and Biland, A. and Billotta, S. and Bird, T. and Birsin, E. and Bissaldi, E. and Blake, S. and Blanch Bigas, O. and Bobkov, A. A. and Bogacz, L. and Bogdan, M. and Boisson, Catherine and Boix Gargallo, J. and Bolmont, J. and Bonanno, G. and Bonardi, A. and Bonev, T. and Borkowski, Janett and Botner, O. and Bottani, A. and Bourgeat, M. and Boutonnet, C. and Bouvier, A. and Brau-Nogue, S. and Braun, I. and Bretz, T. and Briggs, M. S. and Brun, Pierre and Brunetti, L. and Buckley, H. and Bugaev, V. and Buehler, R. and Bulik, Tomasz and Busetto, G. and Buson, S. and Byrum, K. and Cailles, M. and Cameron, R. A. and Canestrari, R. and Cantu, S. and Carmona, E. and Carosi, A. and Carr, John and Carton, P. H. and Casiraghi, M. and Castarede, H. and Catalano, O. and Cavazzani, S. and Cazaux, S. and Cerruti, B. and Cerruti, M. and Chadwick, M. and Chiang, J. and Chikawa, M. and Cieslar, M. and Ciesielska, M. and Cillis, A. N. and Clerc, C. and Colin, P. and Colome, J. and Compin, M. and Conconi, P. and Connaughton, V. and Conrad, Jan and Contreras, J. L. and Coppi, P. and Corlier, M. and Corona, P. and Corpace, O. and Corti, D. and Cortina, J. and Costantini, H. and Cotter, G. and Courty, B. and Couturier, S. and Covino, S. and Croston, J. and Cusumano, G. and Daniel, M. K. and Dazzi, F. and Deangelis, A. and de Cea del Pozo, E. and Dal Pino, E. M. de Gouveia and de Jager, O. and de la Calle Perez, I. and De La Vega, G. and De Lotto, B. and de Naurois, M. and Wilhelmi, E. de Ona and de Souza, V. and Decerprit, B. and Deil, C. and Delagnes, E. and Deleglise, G. and Delgado, C. and Dettlaff, T. and Di Paolo, A. and Di Pierro, F. and Diaz, C. and Dick, J. and Dickinson, H. and Digel, S. W. and Dimitrov, D. and Disset, G. and Djannati-Ata{\"i}, A. and Doert, M. and Domainko, W. and Dorner, D. and Doro, M. and Dournaux, J. -L. and Dravins, D. and Drury, L. and Dubois, F. and Dubois, R. and Dubus, G. and Dufour, C. and Durand, D. and Dyks, J. and Dyrda, M. and Edy, E. and Egberts, Kathrin and Eleftheriadis, C. and Elles, S. and Emmanoulopoulos, D. and Enomoto, R. and Ernenwein, J. -P. and Errando, M. and Etchegoyen, A. and Falcone, A. D. and Farakos, K. and Farnier, C. and Federici, S. and Feinstein, F. and Ferenc, D. and Fillin-Martino, E. and Fink, D. and Finley, C. and Finley, J. P. and Firpo, R. and Florin, D. and Foehr, C. and Fokitis, E. and Font, Ll. and Fontaine, G. and Fontana, A. and Foerster, A. and Fortson, L. and Fouque, N. and Fransson, C. and Fraser, G. W. and Fresnillo, L. and Fruck, C. and Fujita, Y. and Fukazawa, Y. and Funk, S. and Gaebele, W. and Gabici, S. and Gadola, A. and Galante, N. and Gallant, Y. and Garcia, B. and Garcia Lopez, R. J. and Garrido, D. and Garrido, L. and Gascon, D. and Gasq, C. and Gaug, M. and Gaweda, J. and Geffroy, N. and Ghag, C. and Ghedina, A. and Ghigo, M. and Gianakaki, E. and Giarrusso, S. and Giavitto, G. and Giebels, B. and Giro, E. and Giubilato, P. and Glanzman, T. and Glicenstein, J. -F. and Gochna, M. and Golev, V. and Gomez Berisso, M. and Gonzalez, A. and Gonzalez, F. and Granena, F. and Graciani, R. and Granot, J. and Gredig, R. and Green, A. and Greenshaw, T. and Grimm, O. and Grube, J. and Grudzinska, M. and Grygorczuk, J. and Guarino, V. and Guglielmi, L. and Guilloux, F. and Gunji, S. and Gyuk, G. and Hadasch, D. and Haefner, D. and Hagiwara, R. and Hahn, J. and Hallgren, A. and Hara, S. and Hardcastle, M. J. and Hassan, T. and Haubold, T. and Hauser, M. and Hayashida, M. and Heller, R. and Henri, G. and Hermann, G. and Herrero, A. and Hinton, James Anthony and Hoffmann, D. and Hofmann, W. and Hofverberg, P. and Horns, D. and Hrupec, D. and Huan, H. and Huber, B. and Huet, J. -M. and Hughes, G. and Hultquist, K. and Humensky, T. B. and Huppert, J. -F. and Ibarra, A. and Illa, J. M. and Ingjald, J. and Inoue, S. and Inoue, Y. and Ioka, K. and Jablonski, C. and Jacholkowska, A. and Janiak, M. and Jean, P. and Jensen, H. and Jogler, T. and Jung, I. and Kaaret, P. and Kabuki, S. and Kakuwa, J. and Kalkuhl, C. and Kankanyan, R. and Kapala, M. and Karastergiou, A. and Karczewski, M. and Karkar, S. and Karlsson, N. and Kasperek, J. and Katagiri, H. and Katarzynski, K. and Kawanaka, N. and Kedziora, B. and Kendziorra, E. and Khelifi, B. and Kieda, D. and Kifune, T. and Kihm, T. and Klepser, S. and Kluzniak, W. and Knapp, J. and Knappy, A. R. and Kneiske, T. and Knoedlseder, J. and Koeck, F. and Kodani, K. and Kohri, K. and Kokkotas, K. and Komin, N. and Konopelko, A. and Kosack, K. and Kossakowski, R. and Kostka, P. and Kotula, J. and Kowal, G. and Koziol, J. and Kraehenbuehl, T. and Krause, J. and Krawczynski, H. and Krennrich, F. and Kretzschmann, A. and Kubo, H. and Kudryavtsev, V. A. and Kushida, J. and La Barbera, N. and La Parola, V. and La Rosa, G. and Lopez, A. and Lamanna, G. and Laporte, P. and Lavalley, C. and Le Flour, T. and Le Padellec, A. and Lenain, J. -P. and Lessio, L. and Lieunard, B. and Lindfors, E. and Liolios, A. and Lohse, T. and Lombardi, S. and Lopatin, A. and Lorenz, E. and Lubinski, P. and Luz, O. and Lyard, E. and Maccarone, M. C. and Maccarone, T. and Maier, G. and Majumdar, P. and Maltezos, S. and Malkiewicz, P. and Mana, C. and Manalaysay, A. and Maneva, G. and Mangano, A. and Manigot, P. and Marin, J. and Mariotti, M. and Markoff, S. and Martinez, G. and Martinez, M. and Mastichiadis, A. and Matsumoto, H. and Mattiazzo, S. and Mazin, D. and McComb, T. J. L. and McCubbin, N. and McHardy, I. and Medina, C. and Melkumyan, D. and Mendes, A. and Mertsch, P. and Meucci, M. and Michalowski, J. and Micolon, P. and Mineo, T. and Mirabal, N. and Mirabel, F. and Miranda, J. M. and Mirzoyan, R. and Mizuno, T. and Moal, B. and Moderski, R. and Molinari, E. and Monteiro, I. and Moralejo, A. and Morello, C. and Mori, K. and Motta, G. and Mottez, F. and Moulin, Emmanuel and Mukherjee, R. and Munar, P. and Muraishi, H. and Murase, K. and Murphy, A. Stj. and Nagataki, S. and Naito, T. and Nakamori, T. and Nakayama, K. and Naumann, C. L. and Naumann, D. and Nayman, P. and Nedbal, D. and Niedzwiecki, A. and Niemiec, J. and Nikolaidis, A. and Nishijima, K. and Nolan, S. J. and Nowak, N. and O'Brien, P. T. and Ochoa, I. and Ohira, Y. and Ohishi, M. and Ohka, H. and Okumura, A. and Olivetto, C. and Ong, R. A. and Orito, R. and Orr, M. and Osborne, J. P. and Ostrowski, M. and Otero, L. and Otte, A. N. and Ovcharov, E. and Oya, I. and Ozieblo, A. and Paiano, S. and Pallota, J. and Panazol, J. L. and Paneque, D. and Panter, M. and Paoletti, R. and Papyan, G. and Paredes, J. M. and Pareschi, G. and Parsons, R. D. and Arribas, M. Paz and Pedaletti, G. and Pepato, A. and Persic, M. and Petrucci, P. O. and Peyaud, B. and Piechocki, W. and Pita, S. and Pivato, G. and Platos, L. and Platzer, R. and Pogosyan, L. and Pohl, Martin and Pojmanski, G. and Ponz, J. D. and Potter, W. and Prandini, E. and Preece, R. and Prokoph, H. and Puehlhofer, G. and Punch, M. and Quel, E. and Quirrenbach, A. and Rajda, P. and Rando, R. and Rataj, M. and Raue, M. and Reimann, C. and Reimann, O. and Reimer, A. and Reimer, O. and Renaud, M. and Renner, S. and Reymond, J. -M. and Rhode, W. and Ribo, M. and Ribordy, M. and Rico, J. and Rieger, F. and Ringegni, P. and Ripken, J. and Ristori, P. and Rivoire, S. and Rob, L. and Rodriguez, S. and Roeser, U. and Romano, Patrizia and Romero, G. E. and Rosier-Lees, S. and Rovero, A. C. and Roy, F. and Royer, S. and Rudak, B. and Rulten, C. B. and Ruppel, J. and Russo, F. and Ryde, F. and Sacco, B. and Saggion, A. and Sahakian, V. and Saito, K. and Saito, T. and Sakaki, N. and Salazar, E. and Salini, A. and Sanchez, F. and Sanchez Conde, M. A. and Santangelo, A. and Santos, E. M. and Sanuy, A. and Sapozhnikov, L. and Sarkar, S. and Scalzotto, V. and Scapin, V. and Scarcioffolo, M. and Schanz, T. and Schlenstedt, S. and Schlickeiser, R. and Schmidt, T. and Schmoll, J. and Schroedter, M. and Schultz, C. and Schultze, J. and Schulz, A. and Schwanke, U. and Schwarzburg, S. and Schweizer, T. and Seiradakis, J. and Selmane, S. and Seweryn, K. and Shayduk, M. and Shellard, R. C. and Shibata, T. and Sikora, M. and Silk, J. and Sillanpaa, A. and Sitarek, J. and Skole, C. and Smith, N. and Sobczynska, D. and Sofo Haro, M. and Sol, H. and Spanier, F. and Spiga, D. and Spyrou, S. and Stamatescu, V. and Stamerra, A. and Starling, R. L. C. and Stawarz, L. and Steenkamp, R. and Stegmann, Christian and Steiner, S. and Stergioulas, N. and Sternberger, R. and Stinzing, F. and Stodulski, M. and Straumann, U. and Suarez, A. and Suchenek, M. and Sugawara, R. and Sulanke, K. H. and Sun, S. and Supanitsky, A. D. and Sutcliffe, P. and Szanecki, M. and Szepieniec, T. and Szostek, A. and Szymkowiak, A. and Tagliaferri, G. and Tajima, H. and Takahashi, H. and Takahashi, K. and Takalo, L. and Takami, H. and Talbot, R. G. and Tam, P. H. and Tanaka, M. and Tanimori, T. and Tavani, M. and Tavernet, J. -P. and Tchernin, C. and Tejedor, L. A. and Telezhinsky, Igor O. and Temnikov, P. and Tenzer, C. and Terada, Y. and Terrier, R. and Teshima, M. and Testa, V. and Tibaldo, L. and Tibolla, O. and Tluczykont, M. and Peixoto, C. J. Todero and Tokanai, F. and Tokarz, M. and Toma, K. and Torres, D. F. and Tosti, G. and Totani, T. and Toussenel, F. and Vallania, P. and Vallejo, G. and van der Walt, J. and van Eldik, C. and Vandenbroucke, J. and Vankov, H. and Vasileiadis, G. and Vassiliev, V. V. and Vegas, I. and Venter, L. and Vercellone, S. and Veyssiere, C. and Vialle, J. P. and Videla, M. and Vincent, P. and Vink, J. and Vlahakis, N. and Vlahos, L. and Vogler, P. and Vollhardt, A. and Volpe, F. and Von Gunten, H. P. and Vorobiov, S. and Wagner, S. and Wagner, R. M. and Wagner, B. and Wakely, S. P. and Walter, P. and Walter, R. and Warwick, R. and Wawer, P. and Wawrzaszek, R. and Webb, N. and Wegner, P. and Weinstein, A. and Weitzel, Q. and Welsing, R. and Wetteskind, H. and White, R. and Wierzcholska, A. and Wilkinson, M. I. and Williams, D. A. and Winde, M. and Wischnewski, R. and Wisniewski, L. and Wolczko, A. and Wood, M. and Xiong, Q. and Yamamoto, T. and Yamaoka, K. and Yamazaki, R. and Yanagita, S. and Yoffo, B. and Yonetani, M. and Yoshida, A. and Yoshida, T. and Yoshikoshi, T. and Zabalza, V. and Zagdanski, A. and Zajczyk, A. and Zdziarski, A. and Zech, Alraune and Zietara, K. and Ziolkowski, P. and Zitelli, V. and Zychowski, P.}, title = {Design concepts for the Cherenkov Telescope Array CTA an advanced facility for ground-based high-energy gamma-ray astronomy}, series = {Experimental astronomy : an international journal on astronomical instrumentation and data analysis}, volume = {32}, journal = {Experimental astronomy : an international journal on astronomical instrumentation and data analysis}, number = {3}, publisher = {Springer}, address = {Dordrecht}, organization = {CTA Consortium}, issn = {0922-6435}, doi = {10.1007/s10686-011-9247-0}, pages = {193 -- 316}, year = {2011}, abstract = {Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTA is based on currently available technology. This document reports on the status and presents the major design concepts of CTA.}, language = {en} } @article{AbramowskiAceroAharonianetal.2012, author = {Abramowski, Attila and Acero, F. and Aharonian, Felix A. and Akhperjanian, A. G. and Anton, Gisela and Balzer, Arnim and Barnacka, Anna and de Almeida, U. Barres and Becherini, Yvonne and Becker, J. and Behera, B. and Bernl{\"o}hr, K. and Birsin, E. and Biteau, Jonathan and Bochow, A. and Boisson, Catherine and Bolmont, J. and Bordas, Pol and Brucker, J. and Brun, Francois and Brun, Pierre and Bulik, Tomasz and Buesching, I. and Carrigan, Svenja and Casanova, Sabrina and Cerruti, M. and Chadwick, Paula M. and Charbonnier, A. and Chaves, Ryan C. G. and Cheesebrough, A. and Clapson, A. C. and Coignet, G. and Cologna, Gabriele and Conrad, Jan and Dalton, M. and Daniel, M. K. and Davids, I. D. and Degrange, B. and Deil, C. and Dickinson, H. J. and Djannati-Ata{\"i}, A. and Domainko, W. and Drury, L. O'C. and Dubus, G. and Dutson, K. and Dyks, J. and Dyrda, M. and Egberts, Kathrin and Eger, P. and Espigat, P. and Fallon, L. and Farnier, C. and Fegan, S. and Feinstein, F. and Fernandes, M. V. and Fiasson, A. and Fontaine, G. and Foerster, A. and Fuessling, M. and Gallant, Y. A. and Gast, H. and Gerard, L. and Gerbig, D. and Giebels, B. and Glicenstein, J. F. and Glueck, B. and Goret, P. and Goering, D. and Haeffner, S. and Hague, J. D. and Hampf, D. and Hauser, M. and Heinz, S. and Heinzelmann, G. and Henri, G. and Hermann, G. and Hinton, James Anthony and Hoffmann, A. and Hofmann, W. and Hofverberg, P. and Holler, M. and Horns, D. and Jacholkowska, A. and de Jager, O. C. and Jahn, C. and Jamrozy, M. and Jung, I. and Kastendieck, M. A. and Katarzynski, K. and Katz, U. and Kaufmann, S. and Keogh, D. and Khangulyan, D. and Khelifi, B. and Klochkov, D. and Kluzniak, W. and Kneiske, T. and Komin, Nu. and Kosack, K. and Kossakowski, R. and Laffon, H. and Lamanna, G. and Lennarz, D. and Lohse, T. and Lopatin, A. and Lu, C. -C. and Marandon, V. and Marcowith, Alexandre and Masbou, J. and Maurin, D. and Maxted, N. and Mayer, M. and McComb, T. J. L. and Medina, M. C. and Mehault, J. and Moderski, R. and Moulin, Emmanuel and Naumann, C. L. and Naumann-Godo, M. and de Naurois, M. and Nedbal, D. and Nekrassov, D. and Nguyen, N. and Nicholas, B. and Niemiec, J. and Nolan, S. J. and Ohm, S. and Wilhelmi, E. de Ona and Opitz, B. and Ostrowski, M. and Oya, I. and Panter, M. and Arribas, M. Paz and Pedaletti, G. and Pelletier, G. and Petrucci, P. -O. and Pita, S. and Puehlhofer, G. and Punch, M. and Quirrenbach, A. and Raue, M. and Rayner, S. M. and Reimer, A. and Reimer, O. and Renaud, M. and de los Reyes, R. and Rieger, F. and Ripken, J. and Rob, L. and Rosier-Lees, S. and Rowell, G. and Rudak, B. and Rulten, C. B. and Ruppel, J. and Sahakian, V. and Sanchez, David M. and Santangelo, A. and Schlickeiser, R. and Schoeck, F. M. and Schulz, A. and Schwanke, U. and Schwarzburg, S. and Schwemmer, S. and Sheidaei, F. and Skilton, J. L. and Sol, H. and Spengler, G. and Stawarz, L. and Steenkamp, R. and Stegmann, Christian and Stinzing, F. and Stycz, K. and Sushch, Iurii and Szostek, A. and Tavernet, J. -P. and Terrier, R. and Tluczykont, M. and Valerius, K. and van Eldik, C. and Vasileiadis, G. and Venter, C. and Vialle, J. P. and Viana, A. and Vincent, P. and Voelk, H. J. and Volpe, F. and Vorobiov, S. and Vorster, M. and Wagner, S. J. and Ward, M. and White, R. and Wierzcholska, A. and Zacharias, M. and Zajczyk, A. and Zdziarski, A. A. and Zech, Alraune and Zechlin, H. -S. and Aleksic, J. and Antonelli, L. A. and Antoranz, P. and Backes, Michael and Barrio, J. A. and Bastieri, D. and Becerra Gonzalez, J. and Bednarek, W. and Berdyugin, A. and Berger, K. and Bernardini, E. and Biland, A. and Blanch Bigas, O. and Bock, R. K. and Boller, A. and Bonnoli, G. and Tridon, D. Borla and Braun, I. and Bretz, T. and Canellas, A. and Carmona, E. and Carosi, A. and Colin, P. and Colombo, E. and Contreras, J. L. and Cortina, J. and Cossio, L. and Covino, S. and Dazzi, F. and De Angelis, A. and De Cea del Pozo, E. and De Lotto, B. and Delgado Mendez, C. and Diago Ortega, A. and Doert, M. and Dominguez, A. and Prester, Dijana Dominis and Dorner, D. and Doro, M. and Elsaesser, D. and Ferenc, D. and Fonseca, M. V. and Font, L. and Fruck, C. and Garcia Lopez, R. J. and Garczarczyk, M. and Garrido, D. and Giavitto, G. and Godinovic, N. and Hadasch, D. and Haefner, D. and Herrero, A. and Hildebrand, D. and Hoehne-Moench, D. and Hose, J. and Hrupec, D. and Huber, B. and Jogler, T. and Klepser, S. and Kraehenbuehl, T. and Krause, J. and La Barbera, A. and Lelas, D. and Leonardo, E. and Lindfors, E. and Lombardi, S. and Lopez, M. and Lorenz, E. and Makariev, M. and Maneva, G. and Mankuzhiyil, N. and Mannheim, K. and Maraschi, L. and Mariotti, M. and Martinez, M. and Mazin, D. and Meucci, M. and Miranda, J. M. and Mirzoyan, R. and Miyamoto, H. and Moldon, J. and Moralejo, A. and Munar, P. and Nieto, D. and Nilsson, K. and Orito, R. and Oya, I. and Paneque, D. and Paoletti, R. and Pardo, S. and Paredes, J. M. and Partini, S. and Pasanen, M. and Pauss, F. and Perez-Torres, M. A. and Persic, M. and Peruzzo, L. and Pilia, M. and Pochon, J. and Prada, F. and Moroni, P. G. Prada and Prandini, E. and Puljak, I. and Reichardt, I. and Reinthal, R. and Rhode, W. and Ribo, M. and Rico, J. and Ruegamer, S. and Saggion, A. and Saito, K. and Saito, T. Y. and Salvati, M. and Satalecka, K. and Scalzotto, V. and Scapin, V. and Schultz, C. and Schweizer, T. and Shayduk, M. and Shore, S. N. and Sillanpaa, A. and Sitarek, J. and Sobczynska, D. and Spanier, F. and Spiro, S. and Stamerra, A. and Steinke, B. and Storz, J. and Strah, N. and Suric, T. and Takalo, L. and Takami, H. and Tavecchio, F. and Temnikov, P. and Terzic, T. and Tescaro, D. and Teshima, M. and Thom, M. and Tibolla, O. and Torres, D. F. and Treves, A. and Vankov, H. and Vogler, P. and Wagner, R. M. and Weitzel, Q. and Zabalza, V. and Zandanel, F. and Zanin, R. and Arlen, T. and Aune, T. and Beilicke, M. and Benbow, W. and Bouvier, A. and Bradbury, S. M. and Buckley, J. H. and Bugaev, V. and Byrum, K. and Cannon, A. and Cesarini, A. and Ciupik, L. and Connolly, M. P. and Cui, W. and Dickherber, R. and Duke, C. and Errando, M. and Falcone, A. and Finley, J. P. and Finnegan, G. and Fortson, L. and Furniss, A. and Galante, N. and Gall, D. and Godambe, S. and Griffin, S. and Grube, J. and Gyuk, G. and Hanna, D. and Holder, J. and Huan, H. and Hui, C. M. and Kaaret, P. and Karlsson, N. and Kertzman, M. and Khassen, Y. and Kieda, D. and Krawczynski, H. and Krennrich, F. and Lang, M. J. and LeBohec, S. and Maier, G. and McArthur, S. and McCann, A. and Moriarty, P. and Mukherjee, R. and Nunez, P. D. and Ong, R. A. and Orr, M. and Otte, A. N. and Park, N. and Perkins, J. S. and Pichel, A. and Pohl, Martin and Prokoph, H. and Ragan, K. and Reyes, L. C. and Reynolds, P. T. and Roache, E. and Rose, H. J. and Ruppel, J. and Schroedter, M. and Sembroski, G. H. and Sentuerk, G. D. and Telezhinsky, Igor O. and Tesic, G. and Theiling, M. and Thibadeau, S. and Varlotta, A. and Vassiliev, V. V. and Vivier, M. and Wakely, S. P. and Weekes, T. C. and Williams, D. A. and Zitzer, B. and de Almeida, U. Barres and Cara, M. and Casadio, C. and Cheung, C. C. and McConville, W. and Davies, F. and Doi, A. and Giovannini, G. and Giroletti, M. and Hada, K. and Hardee, P. and Harris, D. E. and Junor, W. and Kino, M. and Lee, N. P. and Ly, C. and Madrid, J. and Massaro, F. and Mundell, C. G. and Nagai, H. and Perlman, E. S. and Steele, I. A. and Walker, R. C. and Wood, D. L.}, title = {The 2010 very high energy gamma-ray flare and 10 years ofmulti-wavelength oservations of M 87}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, volume = {746}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, number = {2}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, organization = {HESS Collaboration, MAGIC Collaboration, VERITAS Collaboration}, issn = {0004-637X}, doi = {10.1088/0004-637X/746/2/151}, pages = {18}, year = {2012}, abstract = {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.}, language = {en} } @article{AbeysekaraArcherBenbowetal.2018, author = {Abeysekara, A. U. and Archer, A. and Benbow, Wystan and Bird, Ralph and Brose, Robert and Buchovecky, M. and Buckley, J. H. and Bugaev, V. and Chromey, A. J. and Connolly, M. P. and Cui, Wei and Daniel, M. K. and Falcone, A. and Feng, Qi and Finley, John P. and Fortson, L. and Furniss, Amy and Huetten, M. and Hanna, David and Hervet, O. and Holder, J. and Hughes, G. and Humensky, T. B. and Johnson, Caitlin A. and Kaaret, Philip and Kar, P. and Kertzman, M. and Kieda, David and Krause, M. and Krennrich, F. and Kumar, S. and Lang, M. J. and Lin, T. T. Y. and McArthur, S. and Moriarty, P. and Mukherjee, Reshmi and Ong, R. A. and Otte, Adam Nepomuk and Park, Nahee and Petrashyk, A. and Pohl, Martin and Pueschel, Elisa and Quinn, J. and Ragan, K. and Reynolds, P. T. and Richards, Gregory T. and Roache, E. and Rulten, C. and Sadeh, I. and Santander, Marcos and Sembroski, G. H. and Shahinyan, Karlen and Sushch, I. and Tyler, J. and Wakely, S. P. and Weinstein, A. and Wells, R. M. and Wilcox, P. and Wilhelm, Alina and Williams, D. A. and Williamson, T. J. and Zitzer, B. and Abdollahi, S. and Ajello, Marco and Baldini, Luca and Barbiellini, G. and Bastieri, Denis and Bellazzini, Ronaldo and Berenji, B. and Bissaldi, Elisabetta and Blandford, R. D. and Bonino, R. and Bottacini, E. and Brandt, Terri J. and Bruel, P. and Buehler, R. and Cameron, R. A. and Caputo, R. and Caraveo, P. A. and Castro, D. and Cavazzuti, E. and Charles, Eric and Chiaro, G. and Ciprini, S. and Cohen-Tanugi, Johann and Costantin, D. and Cutini, S. and de Palma, F. and Di Lalla, N. and Di Mauro, M. and Di Venere, L. and Dominguez, A. and Favuzzi, C. and Fegan, S. J. and Franckowiak, Anna and Fukazawa, Yasushi and Funk, Stefan and Fusco, Piergiorgio and Gargano, Fabio and Gasparrini, Dario and Giglietto, Nicola and Giordano, F. and Giroletti, Marcello and Green, D. and Grenier, I. A. and Guillemot, L. and Guiriec, Sylvain and Hays, Elizabeth and Hewitt, John W. and Horan, D. and Johannesson, G. and Kensei, S. and Kuss, M. and Larsson, Stefan and Latronico, L. and Lemoine-Goumard, Marianne and Li, J. and Longo, Francesco and Loparco, Francesco and Lovellette, M. N. and Lubrano, Pasquale and Magill, Jeffrey D. and Maldera, Simone and Mazziotta, Mario Nicola and McEnery, J. E. and Michelson, P. F. and Mitthumsiri, W. and Mizuno, Tsunefumi and Monzani, Maria Elena and Morselli, Aldo and Moskalenko, Igor V. and Negro, M. and Nuss, E. and Ojha, R. and Omodei, Nicola and Orienti, M. and Orlando, E. and Palatiello, M. and Paliya, Vaidehi S. and Paneque, D. and Perkins, Jeremy S. and Persic, M. and Pesce-Rollins, Melissa and Petrosian, Vahe' and Piron, F. and Porter, Troy A. and Principe, G. and Raino, S. and Rando, Riccardo and Rani, B. and Razzano, Massimilano and Razzaque, Soebur and Reimer, A. and Reimer, Olaf and Reposeur, T. and Sgro, C. and Siskind, E. J. and Spandre, Gloria and Spinelli, P. and Suson, D. J. and Tajima, Hiroyasu and Thayer, J. B. and Thompson, David J. and Torres, Diego F. and Tosti, Gino and Troja, Eleonora and Valverde, J. and Vianello, Giacomo and Vogel, M. and Wood, K. and Yassine, M. and Alfaro, R. and Alvarez, C. and Alvarez, J. D. and Arceo, R. and Arteaga-Velazquez, J. C. and Rojas, D. Avila and Ayala Solares, H. A. and Becerril, A. and Belmont-Moreno, E. and BenZvi, S. Y. and Bernal, A. and Braun, J. and Brisbois, C. and Caballero-Mora, K. S. and Capistran, T. and Carraminana, A. and Casanova, Sabrina and Castillo, M. and Cotti, U. and Cotzomi, J. and Coutino de Leon, S. and De Leon, C. and De la Fuente, E. and Dichiara, S. and Dingus, B. L. and DuVernois, M. A. and Diaz-Velez, J. C. and Engel, K. and Enriquez-Rivera, O. and Fiorino, D. W. and Fleischhack, H. and Fraija, N. and Garcia-Gonzalez, J. A. and Garfias, F. and Gonzalez Munoz, A. and Gonzalez, M. M. and Goodman, J. A. and Hampel-Arias, Z. and Harding, J. P. and Hernandez, S. and Hernandez-Almada, A. and Hona, B. and Hueyotl-Zahuantitla, F. and Hui, C. M. and Huntemeyer, P. and Iriarte, A. and Jardin-Blicq, A. and Joshi, V. and Kaufmann, S. and Lara, A. and Lauer, R. J. and Lee, W. H. and Lennarz, D. and Leon Vargas, H. and Linnemann, J. T. and Longinotti, A. L. and Luis-Raya, G. and Luna-Garcia, R. and Lopez-Coto, R. and Malone, K. and Marinelli, S. S. and Martinez, O. and Martinez-Castellanos, I. and Martinez-Castro, J. and Martinez-Huerta, H. and Matthews, J. A. and Miranda-Romagnoli, P. and Moreno, E. and Mostafa, M. and Nayerhoda, A. and Nellen, L. and Newbold, M. and Nisa, M. U. and Noriega-Papaqui, R. and Pelayo, R. and Pretz, J. and Perez-Perez, E. G. and Ren, Z. and Rho, C. D. and Riviere, C. and Rosa-Gonzalez, D. and Rosenberg, M. and Ruiz-Velasco, E. and Salazar, H. and Greus, F. Salesa and Sandoval, A. and Schneider, M. and Arroyo, M. Seglar and Sinnis, G. and Smith, A. J. and Springer, R. W. and Surajbali, P. and Taboada, Ignacio and Tibolla, O. and Tollefson, K. and Torres, I. and Ukwatta, Tilan N. and Villasenor, L. and Weisgarber, T. and Westerhoff, Stefan and Wisher, I. G. and Wood, J. and Yapici, Tolga and Yodh, G. and Zepeda, A. and Zhou, H.}, title = {VERITAS and Fermi-LAT Observations of TeV Gamma-Ray Sources Discovered by HAWC in the 2HWC Catalog}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, volume = {866}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, number = {1}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, organization = {VERITAS Collaboration Fermi-LAT Collaboration HAWC Collaboration}, issn = {0004-637X}, doi = {10.3847/1538-4357/aade4e}, pages = {18}, year = {2018}, abstract = {The High Altitude Water Cherenkov (HAWC) collaboration recently published their 2HWC catalog, listing 39 very high energy (VHE; >100 GeV) gamma-ray sources based on 507 days of observation. Among these, 19 sources are not associated with previously known teraelectronvolt (TeV) gamma-ray sources. We have studied 14 of these sources without known counterparts with VERITAS and Fermi-LAT. VERITAS detected weak gamma-ray emission in the 1 TeV-30 TeV band in the region of DA 495, a pulsar wind nebula coinciding with 2HWC J1953+294, confirming the discovery of the source by HAWC. We did not find any counterpart for the selected 14 new HAWC sources from our analysis of Fermi-LAT data for energies higher than 10 GeV. During the search, we detected gigaelectronvolt (GeV) gamma-ray emission coincident with a known TeV pulsar wind nebula, SNR G54.1+0.3 (VER J1930+188), and a 2HWC source, 2HWC J1930+188. The fluxes for isolated, steady sources in the 2HWC catalog are generally in good agreement with those measured by imaging atmospheric Cherenkov telescopes. However, the VERITAS fluxes for SNR G54.1+0.3, DA 495, and TeV J2032+4130 are lower than those measured by HAWC, and several new HAWC sources are not detected by VERITAS. This is likely due to a change in spectral shape, source extension, or the influence of diffuse emission in the source region.}, language = {en} } @article{AhnenAnsoldiAntonellietal.2018, author = {Ahnen, M. L. and Ansoldi, S. and Antonelli, L. A. and Arcaro, C. and Babic, A. and Banerjee, B. and Bangale, P. and Barres de Almeida, U. and Barrio, J. A. and Gonzalez, J. Becerra and Bednarek, W. and Bernardini, E. and Berti, A. and Bhattacharyya, W. and Blanch, O. and Bonnoli, G. and Carosi, R. and Carosi, A. and Chatterjee, A. and Colak, S. M. and Colin, P. and Colombo, E. and Contreras, J. L. and Cortina, J. and Covino, S. and Cumani, P. and Da Vela, P. and Dazzi, F. and De Angelis, A. and De Lotto, B. and Delfino, M. and Delgado, Jose Miguel Martins and Di Pierro, F. and Doert, M. and Dominguez, A. and Prester, D. Dominis and Doro, M. and Glawion, D. Eisenacher and Engelkemeier, M. and Ramazani, V. Fallah and Fernandez-Barral, A. and Fidalgo, D. and Fonseca, M. V. and Font, L. and Fruck, C. and Galindo, D. and Lopez, R. J. Garcia and Garczarczyk, M. and Gaug, M. and Giammaria, P. and Godinovic, N. and Gora, D. and Guberman, D. and Hadasch, D. and Hahn, A. and Hassan, T. and Hayashida, M. and Herrera, J. and Hose, J. and Hrupec, D. and Ishio, K. and Konno, Y. and Kubo, H. and Kushida, J. and Kuvezdic, D. and Lelas, D. and Lindfors, E. and Lombardi, S. and Longo, F. and Lopez, M. and Maggio, C. and Majumdar, P. and Makariev, M. and Maneva, G. and Manganaro, M. and Maraschi, L. and Mariotti, M. and Martinez, M. and Mazin, D. and Menzel, U. and Minev, M. and Miranda, J. M. and Mirzoyan, R. and Moralejo, A. and Moreno, V. and Moretti, E. and Nagayoshi, T. and Neustroev, V. and Niedzwiecki, A. and Nievas Rosillo, M. and Nigro, C. and Nilsson, K. and Ninci, D. and Nishijima, K. and Noda, K. and Nogues, L. and Paiano, S. and Palacio, J. and Paneque, D. and Paoletti, R. and Paredes, J. M. and Pedaletti, G. and Peresano, M. and Perri, L. and Persic, M. and Moroni, P. G. Prada and Prandini, E. and Puljak, I. and Garcia, J. R. and Reichardt, I. and Ribo, M. and Rico, J. and Righi, C. and Rugliancich, A. and Saito, T. and Satalecka, K. and Schroeder, S. and Schweizer, T. and Shore, S. N. and Sitarek, J. and Snidaric, I. and Sobczynska, D. and Stamerra, A. and Strzys, M. and Suric, T. and Takalo, L. and Tavecchio, F. and Temnikov, P. and Terzic, T. and Teshima, M. and Torres-Alba, N. and Treves, A. and Tsujimoto, S. and Vanzo, G. and Vazquez Acosta, M. and Vovk, I. and Ward, J. E. and Will, M. and Zaric, D. and Arbet-Engels, A. and Baack, D. and Balbo, M. and Biland, A. and Blank, M. and Bretz, T. and Bruegge, K. and Bulinski, M. and Buss, J. and Dmytriiev, A. and Dorner, D. and Einecke, S. and Elsaesser, D. and Herbst, T. and Hildebrand, D. and Kortmann, L. and Linhoff, L. and Mahlke, M. and Mannheim, K. and Mueller, S. A. and Neise, D. and Neronov, A. and Noethe, M. and Oberkirch, J. and Paravac, A. and Rhode, W. and Schleicher, B. and Schulz, F. and Sedlaczek, K. and Shukla, A. and Sliusar, V. and Walter, R. and Archer, A. and Benbow, W. and Bird, R. and Brose, Robert and Buckley, J. H. and Bugaev, V. and Christiansen, J. L. and Cui, W. and Daniel, M. K. and Falcone, A. and Feng, Q. and Finley, J. P. and Gillanders, G. H. and Gueta, O. and Hanna, D. and Hervet, O. and Holder, J. and Hughes, G. and Huetten, M. and Humensky, T. B. and Johnson, C. A. and Kaaret, P. and Kar, P. and Kelley-Hoskins, N. and Kertzman, M. and Kieda, D. and Krause, M. and Krennrich, F. and Kumar, S. and Lang, M. J. and Lin, T. T. Y. and Maier, G. and McArthur, S. and Moriarty, P. and Mukherjee, R. and Ong, R. A. and Otte, A. N. and Park, N. and Petrashyk, A. and Pichel, A. and Pohl, Martin and Quinn, J. and Ragan, K. and Reynolds, P. T. and Richards, G. T. and Roache, E. and Rovero, A. C. and Rulten, C. and Sadeh, I. and Santander, M. and Sembroski, G. H. and Shahinyan, K. and Sushch, Iurii and Tyler, J. and Wakely, S. P. and Weinstein, A. and Wells, R. M. and Wilcox, P. and Wilhel, A. and Williams, D. A. and Williamson, T. J. and Zitzer, B. and Perri, M. and Verrecchia, F. and Leto, C. and Villata, M. and Raiteri, C. M. and Jorstad, S. G. and Larionov, V. M. and Blinov, D. A. and Grishina, T. S. and Kopatskaya, E. N. and Larionova, E. G. and Nikiforova, A. A. and Morozova, D. A. and Troitskaya, Yu. V. and Troitsky, I. S. and Kurtanidze, O. M. and Nikolashvili, M. G. and Kurtanidze, S. O. and Kimeridze, G. N. and Chigladze, R. A. and Strigachev, A. and Sadun, A. C.}, title = {Extreme HBL behavior of Markarian 501 during 2012}, series = {Astronomy and astrophysics : an international weekly journal / European Southern Observatory (ESO)}, volume = {620}, journal = {Astronomy and astrophysics : an international weekly journal / European Southern Observatory (ESO)}, publisher = {EDP Sciences}, address = {Les Ulis}, organization = {MAGIC Collaboration FACT Collaboration VERITAS Collaboration}, issn = {1432-0746}, doi = {10.1051/0004-6361/201833704}, pages = {23}, year = {2018}, abstract = {Aims. We aim to characterize the multiwavelength emission from Markarian 501 (Mrk 501), quantify the energy-dependent variability, study the potential multiband correlations, and describe the temporal evolution of the broadband emission within leptonic theoretical scenarios. Methods. We organized a multiwavelength campaign to take place between March and July of 2012. Excellent temporal coverage was obtained with more than 25 instruments, including the MAGIC, FACT and VERITAS Cherenkov telescopes, the instruments on board the Swift and Fermi spacecraft, and the telescopes operated by the GASP-WEBT collaboration. Results. Mrk 501 showed a very high energy (VHE) gamma-ray flux above 0.2 TeV of similar to 0.5 times the Crab Nebula flux (CU) for most of the campaign. The highest activity occurred on 2012 June 9, when the VHE flux was similar to 3 CU, and the peak of the high-energy spectral component was found to be at similar to 2 TeV. Both the X-ray and VHE gamma-ray spectral slopes were measured to be extremely hard, with spectral indices <2 during most of the observing campaign, regardless of the X-ray and VHE flux. This study reports the hardest Mrk 501 VHE spectra measured to date. The fractional variability was found to increase with energy, with the highest variability occurring at VHE. Using the complete data set, we found correlation between the X-ray and VHE bands; however, if the June 9 flare is excluded, the correlation disappears (significance <3 sigma) despite the existence of substantial variability in the X-ray and VHE bands throughout the campaign. Conclusions. The unprecedentedly hard X-ray and VHE spectra measured imply that their low- and high-energy components peaked above 5 keV and 0.5 TeV, respectively, during a large fraction of the observing campaign, and hence that Mrk 501 behaved like an extreme high-frequency-peaked blazar (EHBL) throughout the 2012 observing season. This suggests that being an EHBL may not be a permanent characteristic of a blazar, but rather a state which may change over time. The data set acquired shows that the broadband spectral energy distribution (SED) of Mrk 501, and its transient evolution, is very complex, requiring, within the framework of synchrotron self-Compton (SSC) models, various emission regions for a satisfactory description. Nevertheless the one-zone SSC scenario can successfully describe the segments of the SED where most energy is emitted, with a significant correlation between the electron energy density and the VHE gamma-ray activity, suggesting that most of the variability may be explained by the injection of high-energy electrons. The one-zone SSC scenario used reproduces the behavior seen between the measured X-ray and VHE gamma-ray fluxes, and predicts that the correlation becomes stronger with increasing energy of the X-rays.}, language = {en} } @article{FurnissNodaBoggsetal.2015, author = {Furniss, A. and Noda, K. and Boggs, S. and Chiang, J. and Christensen, F. and Craig, W. and Giommi, P. and Hailey, C. and Harisson, F. and Madejski, G. and Nalewajko, K. and Perri, M. and Stern, D. and Urry, M. and Verrecchia, F. and Zhang, W. and Ahnen, M. L. and Ansoldi, S. and Antonelli, L. A. and Antoranz, P. and Babic, A. and Banerjee, B. and Bangale, P. and de Almeida, U. Barres and Barrio, J. A. and Becerra Gonzalez, J. and Bednarek, W. and Bernardini, E. and Biasuzzi, B. and Biland, A. and Blanch Bigas, O. and Bonnefoy, S. and Bonnoli, G. and Borracci, F. and Bretz, T. and Carmona, E. and Carosi, A. and Chatterjee, A. and Clavero, R. and Colin, P. and Colombo, E. and Contreras, J. L. and Cortina, J. and Covino, S. and Da Vela, P. and Dazzi, F. and De Angelis, A. and De Caneva, G. and De Lotto, B. and de Ona Wilhelmi, E. and Delgado Mendez, C. and Di Pierro, F. and Prester, Dijana Dominis and Dorner, D. and Doro, M. and Einecke, S. and Eisenacher Glawion, D. and Elsaesser, D. and Fernandez-Barral, A. and Fidalgo, D. and Fonseca, M. V. and Font, L. and Frantzen, K. and Fruck, C. and Galindo, D. and Garcia Lopez, R. J. and Garczarczyk, M. and Garrido Terrats, D. and Gaug, M. and Giammaria, P. and Godinovic, N. and Gonzalez Munoz, A. and Guberman, D. and Hanabata, Y. and Hayashida, M. and Herrera, J. and Hose, J. and Hrupec, D. and Hughes, G. and Idec, W. and Kellermann, H. and Kodani, K. and Konno, Y. and Kubo, H. and Kushida, J. and La Barbera, A. and Lelas, D. and Lewandowska, N. and Lindfors, E. and Lombardi, S. and Longo, F. and Lopez, M. and Lopez-Coto, R. and Lopez-Oramas, A. and Lorenz, E. and Majumdar, P. and Makariev, M. and Mallot, K. and Maneva, G. and Manganaro, M. and Mannheim, K. and Maraschi, L. and Marcote, B. and Mariotti, M. and Martinez, M. and Mazin, D. and Menzel, U. and Miranda, J. M. and Mirzoyan, R. and Moralejo, A. and Nakajima, D. and Neustroev, V. and Niedzwiecki, A. and Nievas Rosillo, M. and Nilsson, K. and Nishijima, K. and Orito, R. and Overkemping, A. and Paiano, S. and Palacio, J. and Palatiello, M. and Paneque, D. and Paoletti, R. and Paredes, J. M. and Paredes-Fortuny, X. and Persic, M. and Poutanen, J. and Moroni, P. G. Prada and Prandini, E. and Puljak, I. and Reinthal, R. and Rhode, W. and Ribo, M. and Rico, J. and Garcia, J. Rodriguez and Saito, T. and Saito, K. and Satalecka, K. and Scapin, V. and Schultz, C. and Schweizer, T. and Shore, S. N. and Sillanpaa, A. and Sitarek, J. and Snidaric, I. and Sobczynska, D. and Stamerra, A. and Steinbring, T. and Strzys, M. and Takalo, L. and Takami, H. and Tavecchio, F. and Temnikov, P. and Terzic, T. and Tescaro, D. and Teshima, M. and Thaele, J. and Torres, D. F. and Toyama, T. and Treves, A. and Verguilov, V. and Vovk, I. and Will, M. and Zanin, R. and Archer, A. and Benbow, W. and Bird, R. and Biteau, Jonathan and Bugaev, V. and Cardenzana, J. V. and Cerruti, M. and Chen, Xuhui and Ciupik, L. and Connolly, M. P. and Cui, W. and Dickinson, H. J. and Dumm, J. and Eisch, J. D. and Falcone, A. and Feng, Q. and Finley, J. P. and Fleischhack, H. and Fortin, P. and Fortson, L. and Gerard, L. and Gillanders, G. H. and Griffin, S. and Griffiths, S. T. and Grube, J. and Gyuk, G. and Hakansson, Nils and Holder, J. and Humensky, T. B. and Johnson, C. A. and Kaaret, P. and Kertzman, M. and Kieda, D. and Krause, M. and Krennrich, F. and Lang, M. J. and Lin, T. T. Y. and Maier, G. and McArthur, S. and McCann, A. and Meagher, K. and Moriarty, P. and Mukherjee, R. and Nieto, D. and Ong, R. A. and Park, N. and Petry, D. and Pohl, Martin and Popkow, A. and Ragan, K. and Ratliff, G. and Reyes, L. C. and Reynolds, P. T. and Richards, G. T. and Roache, E. and Santander, M. and Sembroski, G. H. and Shahinyan, K. and Staszak, D. and Telezhinsky, Igor O. and Tucci, J. V. and Tyler, J. and Vassiliev, V. V. and Wakely, S. P. and Weiner, O. M. and Weinstein, A. and Wilhelm, Alina and Williams, D. A. and Zitzer, B. and Vince, O. and Fuhrmann, L. and Angelakis, E. and Karamanavis, V. and Myserlis, I. and Krichbaum, T. P. and Zensus, J. A. and Ungerechts, H. and Sievers, A. and Bachev, R. and Boettcher, Markus and Chen, W. P. and Damljanovic, G. and Eswaraiah, C. and Guver, T. and Hovatta, T. and Hughes, Z. and Ibryamov, S. I. and Joner, M. D. and Jordan, B. and Jorstad, S. G. and Joshi, M. and Kataoka, J. and Kurtanidze, O. M. and Kurtanidze, S. O. and Lahteenmaki, A. and Latev, G. and Lin, H. C. and Larionov, V. M. and Mokrushina, A. A. and Morozova, D. A. and Nikolashvili, M. G. and Raiteri, C. M. and Ramakrishnan, V. and Readhead, A. C. R. and Sadun, A. C. and Sigua, L. A. and Semkov, E. H. and Strigachev, A. and Tammi, J. and Tornikoski, M. and Troitskaya, Y. V. and Troitsky, I. S. and Villata, M.}, title = {First NuSTAR observations of MRK 501 within a radio to TeV multi-instrument campaign}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, volume = {812}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, number = {1}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, organization = {NuSTAR Team, MAGIC Collaboration, VERITAS Collaboration, F-Gamma Consortium}, issn = {0004-637X}, doi = {10.1088/0004-637X/812/1/65}, pages = {22}, year = {2015}, abstract = {We report on simultaneous broadband observations of the TeV-emitting blazar Markarian 501 between 2013 April 1 and August 10, including the first detailed characterization of the synchrotron peak with Swift and NuSTAR. During the campaign, the nearby BL Lac object was observed in both a quiescent and an elevated state. The broadband campaign includes observations with NuSTAR, MAGIC, VERITAS, the Fermi Large Area Telescope, Swift X-ray Telescope and UV Optical Telescope, various ground-based optical instruments, including the GASP-WEBT program, as well as radio observations by OVRO, Metsahovi, and the F-Gamma consortium. Some of the MAGIC observations were affected by a sand layer from the Saharan desert, and had to be corrected using event-by-event corrections derived with a Light Detection and Ranging (LIDAR) facility. This is the first time that LIDAR information is used to produce a physics result with Cherenkov Telescope data taken during adverse atmospheric conditions, and hence sets a precedent for the current and future ground-based gamma-ray instruments. The NuSTAR instrument provides unprecedented sensitivity in hard X-rays, showing the source to display a spectral energy distribution (SED) between 3 and 79 keV consistent with a log-parabolic spectrum and hard X-ray variability on hour timescales. None (of the four extended NuSTAR observations) show evidence of the onset of inverse-Compton emission at hard X-ray energies. We apply a single-zone equilibrium synchrotron self-Compton (SSC) model to five simultaneous broadband SEDs. We find that the SSC model can reproduce the observed broadband states through a decrease in the magnetic field strength coinciding with an increase in the luminosity and hardness of the relativistic leptons responsible for the high-energy emission.}, language = {en} } @article{AbeysekaraBenbowBirdetal.2018, author = {Abeysekara, A. U. and Benbow, Wystan and Bird, Ralph and Brill, A. and Brose, Robert and Buckley, J. H. and Chromey, A. J. and Daniel, M. K. and Falcone, A. and Finley, J. P. and Fortson, L. and Furniss, Amy and Gent, A. and Gillanders, Gerald H. and Hanna, David and Hassan, T. and Hervet, O. and Holder, J. and Hughes, G. and Humensky, T. B. and Kaaret, Philip and Kar, P. and Kertzman, M. and Kieda, David and Krause, Maria and Krennrich, F. and Kumar, S. and Lang, M. J. and Lin, T. T. Y. and Maier, Gernot and Moriarty, P. and Mukherjee, Reshmi and Ong, R. A. and Otte, Adam Nepomuk and Park, Nahee and Petrashyk, A. and Pohl, Martin and Pueschel, Elisa and Quinn, J. and Ragan, K. and Richards, Gregory T. and Roache, E. and Sadeh, I. and Santander, Marcos and Schlenstedt, S. and Sembroski, G. H. and Sushch, Iurii and Tyler, J. and Vassiliev, V. V. and Wakely, S. P. and Weinstein, A. and Wells, R. M. and Wilcox, P. and Wilhelm, Alina and Williams, David A. and Williamson, T. J. and Zitzer, B. and Acciari, V. A. and Ansoldi, S. and Antonelli, L. A. and Engels, A. Arbet and Baack, D. and Babic, A. and Banerjee, B. and de Almeida, U. Barres and Barrio, J. A. and Becerra Gonzalez, Josefa and Bednarek, Wlodek and Bernardini, Elisa and Berti, A. and Besenrieder, J. and Bhattacharyya, W. and Bigongiari, C. and Biland, A. and Blanch, O. and Bonnoli, G. and Busetto, G. and Carosi, R. and Ceribella, G. and Cikota, S. and Colak, S. M. and Colin, P. and Colombo, E. and Contreras, J. L. and Cortina, J. and Covino, S. and Da Vela, P. and Dazzi, F. and De Angelis, A. and De Lotto, B. and Delfino, M. and Delgado, J. and Di Pierro, F. and Do Souto Espinera, E. and Dominguez, A. and Prester, D. Dominis and Dorner, D. and Doro, M. and Einecke, S. and Elsaesser, D. and Ramazani, V. Fallah and Fattorini, A. and Fernandez-Barral, A. and Ferrara, G. and Fidalgo, D. and Foffano, L. and Fonseca, M. V. and Font, L. and Fruck, C. and Galindo, D. and Gallozzi, S. and Lopez, R. J. Garcia and Garczarczyk, M. and Gasparyan, S. and Gaug, Markus and Giammaria, P. and Godinovic, N. and Guberman, D. and Hadasch, D. and Hahn, A. and Herrera, J. and Hoang, J. and Hrupec, D. and Inoue, S. and Ishio, K. and Iwamura, Y. and Kubo, H. and Kushida, J. and Kuvezdic, D. and Lamastra, A. and Lelas, D. and Leone, Francesco and Lindfors, E. and Lombardi, S. and Longo, Francesco and Lopez, M. and Lopez-Oramas, A. and Machado de Oliveira Fraga, B. and Maggio, C. and Majumdar, P. and Makariev, M. and Mallamaci, M. and Maneva, G. and Manganaro, M. and Mannheim, K. and Maraschi, L. and Mariotti, M. and Martinez, M. and Masuda, S. and Mazin, D. and Minev, M. and Miranda, J. M. and Mirzoyan, R. and Molina, E. and Moralejo, A. and Moreno, V. and Moretti, E. and Munar-Adrover, Pere and Neustroev, V. and Niedzwiecki, Andrzej and Rosillo, Mireia Nievas and Nigro, C. and Nilsson, Kari and Ninci, D. and Nishijima, K. and Noda, K. and Nogues, L. and Noethe, M. and Paiano, Simona and Palacio, J. and Paneque, D. and Paoletti, R. and Paredes, J. M. and Pedaletti, G. and Penil, P. and Peresano, M. and Persic, M. and Moroni, P. G. Prada and Prandini, E. and Puljak, I. and Garcia, J. R. and Rhode, W. and Ribo, Marc and Rico, J. and Righi, C. and Rugliancich, A. and Saha, Lab and Sahakyan, Narek and Saito, T. and Satalecka, K. and Schweizer, T. and Sitarek, J. and Snidaric, I. and Sobczynska, D. and Somero, A. and Stamerra, A. and Strzys, M. and Suric, T. and Tavecchio, Fabrizio and Temnikov, P. and Terzic, T. and Teshima, M. and Torres-Alba, N. and Tsujimoto, S. and van Scherpenberg, J. and Vanzo, G. and Vazquez Acosta, M. and Vovk, I. and Will, M. and Zaric, D.}, title = {Periastron Observations of TeV Gamma-Ray Emission from a Binary System with a 50-year Period}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics ; Part 2, Letters}, volume = {867}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics ; Part 2, Letters}, number = {1}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, organization = {VERITAS Collaboration MAGIC Collaboration}, issn = {2041-8205}, doi = {10.3847/2041-8213/aae70e}, pages = {8}, year = {2018}, abstract = {We report on observations of the pulsar/Be star binary system PSR J2032+4127/MT91 213 in the energy range between 100 GeV and 20 TeV with the Very Energetic Radiation Imaging Telescope Array and Major Atmospheric Gamma Imaging Cherenkov telescope arrays. The binary orbit has a period of approximately 50 years, with the most recent periastron occurring on 2017 November 13. Our observations span from 18 months prior to periastron to one month after. A new point-like gamma-ray source is detected, coincident with the location of PSR J2032+4127/MT91 213. The gamma-ray light curve and spectrum are well characterized over the periastron passage. The flux is variable over at least an order of magnitude, peaking at periastron, thus providing a firm association of the TeV source with the pulsar/Be star system. Observations prior to periastron show a cutoff in the spectrum at an energy around 0.5 TeV. This result adds a new member to the small population of known TeV binaries, and it identifies only the second source of this class in which the nature and properties of the compact object are firmly established. We compare the gamma-ray results with the light curve measured with the X-ray Telescope on board the Neil Gehrels Swift Observatory and with the predictions of recent theoretical models of the system. We conclude that significant revision of the models is required to explain the details of the emission that we have observed, and we discuss the relationship between the binary system and the overlapping steady extended source, TeV J2032+4130.}, language = {en} } @article{ArchambaultAuneBeheraetal.2014, author = {Archambault, S. and Aune, T. and Behera, B. and Beilicke, M. and Benbow, W. and Berger, K. and Bird, R. and Biteau, Jonathan and Bugaev, V. and Byrum, K. and Cardenzana, J. V. and Cerruti, M. and Chen, Xuhui and Ciupik, L. and Connolly, M. P. and Cui, Wei and Dumm, J. and Errando, M. and Falcone, A. and Federici, Simone and Feng, Q. and Finley, J. P. and Fleischhack, H. and Fortson, L. and Furniss, A. and Galante, N. and Gillanders, G. H. and Griffin, S. and Griffiths, S. T. and Grube, J. and Gyuk, G. and Hanna, D. and Holder, J. and Hughes, G. and Humensky, T. B. and Johnson, C. A. and Kaaret, P. and Kertzman, M. and Khassen, Y. and Kieda, D. and Krawczynski, H. and Krennrich, F. and Kumar, S. and Lang, M. J. and Madhavan, A. S. and Maier, G. and McCann, A. and Meagher, K. and Moriarty, P. and Mukherjee, R. and Nieto, Daniel and Ong, R. A. and Otte, A. N. and Park, N. and Pohl, Martin and Popkow, A. and Prokoph, H. and Quinn, J. and Ragan, K. and Rajotte, J. and Reyes, L. C. and Reynolds, P. T. and Richards, G. T. and Roache, E. and Sembroski, G. H. and Shahinyan, K. and Staszak, D. and Telezhinsky, Igor O. and Tucci, J. V. and Tyler, J. and Varlotta, A. and Vassiliev, V. V. and Vincent, S. and Wakely, S. P. and Weinstein, A. and Welsing, R. and Wilhelm, Alina and Williams, D. A. and Ackermann, Margit and Ajello, M. and Albert, A. and Baldini, L. and Bastieri, D. and Bellazzini, R. and Bissaldi, E. and Bregeon, Johan and Buehler, R. and Buson, S. and Caliandro, G. A. and Cameron, R. A. and Caraveo, P. A. and Cavazzuti, E. and Charles, E. and Chiang, J. and Ciprini, S. and Claus, R. and Cutini, S. and de Angelis, A. and de Palma, F. and Dermer, C. D. and Digel, S. W. and Di Venere, L. and Drell, P. S. and Favuzzi, C. and Franckowiak, A. and Fusco, P. and Gargano, F. and Gasparrini, D. and Giglietto, N. and Giordano, F. and Giroletti, M. and Grenier, I. A. and Guiriec, S. and Jogler, T. and Kuss, M. and Larsson, S. and Latronico, L. and Longo, F. and Loparco, F. and Lubrano, P. and Madejski, G. M. and Mayer, M. and Mazziotta, Mario Nicola and Michelson, P. F. and Mizuno, T. and Monzani, M. E. and Morselli, Aldo and Murgia, S. and Nuss, E. and Ohsugi, T. and Ormes, J. F. and Paneque, D. and Perkins, J. S. and Piron, F. and Pivato, G. and Raino, S. and Razzano, M. and Reimer, A. and Reimer, Olaf and Ritz, S. and Schaal, M. and Sgro, C. and Siskind, E. J. and Spinelli, P. and Takahashi, H. and Tibaldo, L. and Tinivella, M. and Troja, E. and Vianello, G. and Werner, M. and Wood, M.}, title = {Deep broadband observations of the distant gamma-ray blazar PKS 1424+240}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics ; Part 2, Letters}, volume = {785}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics ; Part 2, Letters}, number = {1}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, organization = {VERITAS Collaboration, Fermi LAT Collaboration}, issn = {2041-8205}, doi = {10.1088/2041-8205/785/1/L16}, pages = {8}, year = {2014}, abstract = {We present deep VERITAS observations of the blazar PKS 1424+240, along with contemporaneous Fermi Large Area Telescope, Swift X-ray Telescope, and Swift UV Optical Telescope data between 2009 February 19 and 2013 June 8. This blazar resides at a redshift of z >= 0.6035, displaying a significantly attenuated gamma-ray flux above 100 GeV due to photon absorption via pair-production with the extragalactic background light. We present more than 100 hr of VERITAS observations over three years, a multiwavelength light curve, and the contemporaneous spectral energy distributions. The source shows a higher flux of (2.1 +/- 0.3) x 10(-7) photons m(-2) s(-1) above 120 GeV in 2009 and 2011 as compared to the flux measured in 2013, corresponding to (1.02 +/- 0.08) x 10-7 photons m(-2) s(-1) above 120 GeV. The measured differential very high energy (VHE; E >= 100 GeV) spectral indices are Gamma = 3.8 +/- 0.3, 4.3 +/- 0.6 and 4.5 +/- 0.2 in 2009, 2011, and 2013, respectively. No significant spectral change across the observation epochs is detected. We find no evidence for variability at gamma-ray opacities of greater than tau = 2, where it is postulated that any variability would be small and occur on timescales longer than a year if hadronic cosmic-ray interactions with extragalactic photon fields provide a secondary VHE photon flux. The data cannot rule out such variability due to low statistics.}, language = {en} } @article{AliuArlenAuneetal.2012, author = {Aliu, E. and Arlen, T. and Aune, T. and Beilicke, M. and Benbow, W. and Bouvier, A. and Bradbury, S. M. and Buckley, J. H. and Bugaev, V. and Byrum, K. and Cannon, A. and Cesarini, A. and Ciupik, L. and Collins-Hughes, E. and Connolly, M. P. and Cui, W. and Dickherber, R. and Duke, C. and Errando, M. and Falcone, A. and Finley, J. P. and Finnegan, G. and Fortson, L. and Furniss, A. and Galante, N. and Gall, D. and Godambe, S. and Griffin, S. and Grube, J. and Guenette, R. and Gyuk, G. and Hanna, D. and Holder, J. and Huan, H. and Hughes, G. and Hui, C. M. and Humensky, T. B. and Imran, A. and Kaaret, P. and Karlsson, N. and Kertzman, M. and Kieda, D. and Krawczynski, H. and Krennrich, F. and Lang, M. J. and LeBohec, S. and Madhavan, A. S. and Maier, G. and Majumdar, P. and McArthur, S. and McCann, A. and Moriarty, P. and Mukherjee, R. and Nunez, P. D. and Ong, R. A. and Orr, M. and Otte, A. N. and Park, N. and Perkins, J. S. and Pichel, A. and Pohl, Martin and Prokoph, H. and Quinn, J. and Ragan, K. and Reyes, L. C. and Reynolds, P. T. and Roache, E. and Rose, H. J. and Ruppel, J. and Saxon, D. B. and Schroedter, M. and Sembroski, G. H. and Sentuerk, G. D. and Skole, C. and Staszak, D. and Tesic, G. and Theiling, M. and Thibadeau, S. and Tsurusaki, K. and Tyler, J. and Varlotta, A. and Vassiliev, V. V. and Vincent, S. and Vivier, M. and Wakely, S. P. and Ward, J. E. and Weekes, T. C. and Weinstein, A. and Weisgarber, T. and Williams, D. A. and Zitzer, B.}, title = {Veritas observations of day-scale flaring of M 87 in 2010 April}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, volume = {746}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, number = {2}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, issn = {0004-637X}, doi = {10.1088/0004-637X/746/2/141}, pages = {7}, year = {2012}, abstract = {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.}, language = {en} } @article{AcciariAliuArayaetal.2011, author = {Acciari, V. A. and Aliu, E. and Araya, M. and Arlen, T. and Aune, T. and Beilicke, M. and Benbow, W. and Bradbury, S. M. and Buckley, J. H. and Bugaev, V. and Byrum, K. and Cannon, A. and Cesarini, A. and Ciupik, L. and Collins-Hughes, E. and Cui, W. and Dickherber, R. and Duke, C. and Falcone, A. and Finley, J. P. and Fortson, L. and Furniss, A. and Galante, N. and Gall, D. and Godambe, S. and Griffin, S. and Guenette, R. and Gyuk, G. and Hanna, D. and Holder, J. and Hughes, G. and Hui, C. M. and Humensky, T. B. and Imran, A. and Kaaret, P. and Kertzman, M. and Krawczynski, H. and Krennrich, F. and Madhavan, A. S. and Maier, G. and Majumdar, P. and McArthur, S. and Moriarty, P. and Ong, R. A. and Otte, A. N. and Pandel, D. and Park, N. and Perkins, J. S. and Pohl, Martin and Prokoph, H. and Quinn, J. and Ragan, K. and Reyes, L. C. and Reynolds, P. T. and Roache, E. and Rose, H. J. and Saxon, D. B. and Sembroski, G. H. and Sentuerk, G. D. and Smith, A. W. and Tesic, G. and Theiling, M. and Thibadeau, S. and Varlotta, A. and Vincent, S. and Vivier, M. and Wakely, S. P. and Ward, J. E. and Weekes, T. C. and Weinstein, A. and Weisgarber, T. and Weng, S. and Williams, D. A. and Wood, M. and Zitzer, B.}, title = {Gamma-ray observations of the Be/Pulsar binary 1A 0535+262 during a Giant X-Ray outburst}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, volume = {733}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, number = {2}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, issn = {0004-637X}, doi = {10.1088/0004-637X/733/2/96}, pages = {10}, year = {2011}, abstract = {Giant X-ray outbursts, with luminosities of about 10(37) erg s(-1), are observed roughly every five years from the nearby Be/pulsar binary 1A 0535+262. In this article, we present observations of the source with VERITAS at very high energies (VHEs; E > 100 GeV) triggered by the X-ray outburst in 2009 December. The observations started shortly after the onset of the outburst and provided comprehensive coverage of the episode, as well as the 111 day binary orbit. No VHE emission is evident at any time. We also examined data from the contemporaneous observations of 1A 0535+262 with the Fermi/Large Area Telescope at high-energy photons (E > 0.1 GeV) and failed to detect the source at GeV energies. The X-ray continua measured with the Swift/X-Ray Telescope and the RXTE/PCA can be well described by the combination of blackbody and Comptonized emission from thermal electrons. Therefore, the gamma-ray and X-ray observations suggest the absence of a significant population of non-thermal particles in the system. This distinguishes 1A 0535+262 from those Be X-ray binaries (such as PSR B1259-63 and LS I +61 degrees 303) that have been detected at GeV-TeV energies. We discuss the implications of the results on theoretical models.}, language = {en} } @article{AcciariAliuArlenetal.2011, author = {Acciari, V. A. and Aliu, E. and Arlen, T. and Aune, T. and Beilicke, M. and Benbow, W. and Bradbury, S. M. and Buckley, J. H. and Bugaev, V. and Byrum, K. and Cannon, A. and Cesarini, A. and Christiansen, J. L. and Ciupik, L. and Collins-Hughes, E. and Connolly, M. P. and Cui, W. and Duke, C. and Errando, M. and Falcone, A. and Finley, J. P. and Finnegan, G. and Fortson, L. and Furniss, A. and Galante, N. and Gall, D. and Godambe, S. and Griffin, S. and Grube, J. and Guenette, R. and Gyuk, G. and Hanna, D. and Holder, J. and Hughes, G. and Hui, C. M. and Humensky, T. B. and Jackson, D. J. and Kaaret, P. and Karlsson, N. and Kertzman, M. and Kieda, D. and Krawczynski, H. and Krennrich, F. and Lang, M. J. and Madhavan, A. S. and Maier, G. and McArthur, S. and McCann, A. and Moriarty, P. and Newbold, M. D. and Ong, R. A. and Orr, M. and Otte, A. N. and Park, N. and Perkins, J. S. and Pohl, Martin and Prokoph, H. and Quinn, J. and Ragan, K. and Reyes, L. C. and Reynolds, P. T. and Roache, E. and Rose, H. J. and Ruppel, J. and Saxon, D. B. and Schroedter, M. and Sembroski, G. H. and Sentuerk, G. D. and Smith, A. W. and Staszak, D. and Swordy, S. P. and Tesic, G. and Theiling, M. and Thibadeau, S. and Tsurusaki, K. and Varlotta, A. and Vassiliev, V. V. and Vincent, S. and Vivier, M. and Wakely, S. P. and Ward, J. E. and Weekes, T. C. and Weinstein, A. and Weisgarber, T. and Williams, D. A. and Wood, M.}, title = {Veritas observations of gamma-ray bursts detected by swift}, series = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, volume = {743}, journal = {The astrophysical journal : an international review of spectroscopy and astronomical physics}, number = {1}, publisher = {IOP Publ. Ltd.}, address = {Bristol}, issn = {0004-637X}, doi = {10.1088/0004-637X/743/1/62}, pages = {10}, year = {2011}, abstract = {We present the results of 16 Swift-triggered Gamma-ray burst (GRB) follow-up observations taken with the Very Energetic Radiation Imaging Telescope Array System (VERITAS) telescope array from 2007 January to 2009 June. The median energy threshold and response time of these observations were 260 GeV and 320 s, respectively. Observations had an average duration of 90 minutes. Each burst is analyzed independently in two modes: over the whole duration of the observations and again over a shorter timescale determined by the maximum VERITAS sensitivity to a burst with a t(-1.5) time profile. This temporal model is characteristic of GRB afterglows with high-energy, long-lived emission that have been detected by the Large Area Telescope on board the Fermi satellite. No significant very high energy (VHE) gamma-ray emission was detected and upper limits above the VERITAS threshold energy are calculated. The VERITAS upper limits are corrected for gamma-ray extinction by the extragalactic background light and interpreted in the context of the keV emission detected by Swift. For some bursts the VHE emission must have less power than the keV emission, placing constraints on inverse Compton models of VHE emission.}, language = {en} }