Refine
Has Fulltext
- no (14)
Author
- Krennrich, F. (14) (remove)
Language
- English (14)
Is part of the Bibliography
- yes (14)
Keywords
- gamma rays: galaxies (4)
- BL Lacertae objects: general (3)
- galaxies: active (2)
- galaxies: nuclei (2)
- gamma-rays: general (2)
- Air showers (1)
- BL Lacertae objects: individual (1ES 1959+650) (1)
- BL Lacertae objects: individual (B2 1215+30, VER J1217+301) (1)
- BL Lacertae objects: individual: 1ES 2344+514=VERJ2347+517 (1)
- BL Lacertae objects: individual: Mrk 501 (1)
Institute
Introducing the CTA concept
(2013)
Acharya, B. S. ; Actis, M. ; Aghajani, T. ; Agnetta, G. ; Aguilar, J. ; Aharonian, Felix A. ; Ajello, M. ; Akhperjanian, A. G. ; Alcubierre, M. ; Aleksic, J. ; Alfaro, R. ; Aliu, E. ; Allafort, A. J. ; Allan, D. ; Allekotte, I. ; Amato, E. ; Anderson, J. ; Angüner, Ekrem Oǧuzhan ; Antonelli, L. A. ; Antoranz, P. ; Aravantinos, A. ; Arlen, T. ; Armstrong, T. ; Arnaldi, H. ; Arrabito, L. ; Asano, K. ; Ashton, T. ; Asorey, H. G. ; Awane, Y. ; Baba, H. ; Babic, A. ; Baby, N. ; Baehr, J. ; Bais, A. ; Baixeras, C. ; Bajtlik, S. ; Balbo, M. ; Balis, D. ; Balkowski, C. ; Bamba, A. ; Bandiera, R. ; Barber, A. ; Barbier, C. ; Barcelo, M. ; Barnacka, Anna ; Barnstedt, Jürgen ; Barres de Almeida, U. ; Barrio, J. A. ; Basili, A. ; Basso, S. ; Bastieri, D. ; Bauer, C. ; Baushev, Anton N. ; Becerra Gonzalez, J. ; Becherini, Yvonne ; Bechtol, K. C. ; Tjus, J. Becker ; Beckmann, Volker ; Bednarek, W. ; Behera, B. ; Belluso, M. ; Benbow, W. ; Berdugo, J. ; Berger, K. ; Bernard, F. ; Bernardino, T. ; Bernlöhr, K. ; Bhat, N. ; Bhattacharyya, S. ; Bigongiari, C. ; Biland, A. ; Billotta, S. ; Bird, T. ; Birsin, E. ; Bissaldi, E. ; Biteau, Jonathan ; Bitossi, M. ; Blake, S. ; Blanch Bigas, O. ; Blasi, P. ; Bobkov, A. A. ; Boccone, V. ; Boettcher, Markus ; Bogacz, L. ; Bogart, J. ; Bogdan, M. ; Boisson, Catherine ; Boix Gargallo, J. ; Bolmont, J. ; Bonanno, G. ; Bonardi, A. ; Bonev, T. ; Bonifacio, P. ; Bonnoli, G. ; Bordas, Pol ; Borgland, A. W. ; Borkowski, Janett ; Bose, R. ; Botner, O. ; Bottani, A. ; Bouchet, L. ; Bourgeat, M. ; Boutonnet, C. ; Bouvier, A. ; Brau-Nogue, S. ; Braun, I. ; Bretz, T. ; Briggs, M. S. ; Bringmann, T. ; Brook, P. ; Brun, Pierre ; Brunetti, L. ; Buanes, T. ; Buckley, J. H. ; Buehler, R. ; Bugaev, V. ; Bulgarelli, A. ; Bulik, Tomasz ; Busetto, G. ; Buson, S. ; Byrum, K. ; Cailles, M. ; Cameron, R. A. ; Camprecios, J. ; Canestrari, R. ; Cantu, S. ; Capalbi, M. ; Caraveo, P. A. ; Carmona, E. ; Carosi, A. ; Carr, John ; Carton, P. H. ; Casanova, Sabrina ; Casiraghi, M. ; Catalano, O. ; Cavazzani, S. ; Cazaux, S. ; Cerruti, M. ; Chabanne, E. ; Chadwick, Paula M. ; Champion, C. ; Chen, Andrew ; Chiang, J. ; Chiappetti, L. ; Chikawa, M. ; Chitnis, V. R. ; Chollet, F. ; Chudoba, J. ; Cieslar, M. ; Cillis, A. N. ; Cohen-Tanugi, J. ; Colafrancesco, Sergio ; Colin, P. ; Calome, J. ; Colonges, S. ; Compin, M. ; Conconi, P. ; Conforti, V. ; Connaughton, V. ; Conrad, Jan ; Contreras, J. L. ; Coppi, P. ; Corona, P. ; Corti, D. ; Cortina, J. ; Cossio, L. ; Costantini, H. ; Cotter, G. ; Courty, B. ; Couturier, S. ; Covino, S. ; Crimi, G. ; Criswell, S. J. ; Croston, J. ; Cusumano, G. ; Dafonseca, M. ; Dale, O. ; Daniel, M. ; Darling, J. ; Davids, I. ; Dazzi, F. ; De Angelis, A. ; De Caprio, V. ; De Frondat, F. ; de Gouveia Dal Pino, E. M. ; de la Calle, I. ; De La Vega, G. A. ; Lopez, R. de los Reyes ; De Lotto, B. ; De Luca, A. ; de Mello Neto, J. R. T. ; de Naurois, M. ; de Oliveira, Y. ; de Ona Wilhelmi, E. ; de Souza, V. ; Decerprit, G. ; Decock, G. ; Deil, C. ; Delagnes, E. ; Deleglise, G. ; Delgado, C. ; Della Volpe, D. ; Demange, P. ; Depaola, G. ; Dettlaff, A. ; Di Paola, A. ; Di Pierro, F. ; Diaz, C. ; Dick, J. ; Dickherber, R. ; Dickinson, H. ; Diez-Blanco, V. ; Digel, S. ; Dimitrov, D. ; Disset, G. ; Djannati-Ataï, A. ; Doert, M. ; Dohmke, M. ; Domainko, W. ; Prester, Dijana Dominis ; Donat, A. ; Dorner, D. ; Doro, M. ; Dournaux, J-L. ; Drake, G. ; Dravins, D. ; Drury, L. ; Dubois, F. ; Dubois, R. ; Dubus, G. ; Dufour, C. ; Dumas, D. ; Dumm, J. ; Durand, D. ; Dyks, J. ; Dyrda, M. ; Ebr, J. ; Edy, E. ; Egberts, Kathrin ; Eger, P. ; Einecke, S. ; Eleftheriadis, C. ; Elles, S. ; Emmanoulopoulos, D. ; Engelhaupt, D. ; Enomoto, R. ; Ernenwein, J-P ; Errando, M. ; Etchegoyen, A. ; Evans, P. ; Falcone, A. ; Fantinel, D. ; Farakos, K. ; Farnier, C. ; Fasola, G. ; Favill, B. ; Fede, E. ; Federici, S. ; Fegan, S. ; Feinstein, F. ; Ferenc, D. ; Ferrando, P. ; Fesquet, M. ; Fiasson, A. ; Fillin-Martino, E. ; Fink, D. ; Finley, C. ; Finley, J. P. ; Fiorini, M. ; Firpo Curcoll, R. ; Flores, H. ; Florin, D. ; Focke, W. ; Foehr, C. ; Fokitis, E. ; Font, L. ; Fontaine, G. ; Fornasa, M. ; Foerster, A. ; Fortson, L. ; Fouque, N. ; Franckowiak, A. ; Fransson, C. ; Fraser, G. ; Frei, R. ; Albuquerque, I. F. M. ; Fresnillo, L. ; Fruck, C. ; Fujita, Y. ; Fukazawa, Y. ; Fukui, Y. ; Funk, S. ; Gaebele, W. ; Gabici, S. ; Gabriele, R. ; Gadola, A. ; Galante, N. ; Gall, D. ; Gallant, Y. ; Gamez-Garcia, J. ; Garcia, B. ; Garcia Lopez, R. ; Gardiol, D. ; Garrido, D. ; Garrido, L. ; Gascon, D. ; Gaug, M. ; Gaweda, J. ; Gebremedhin, L. ; Geffroy, N. ; Gerard, L. ; Ghedina, A. ; Ghigo, M. ; Giannakaki, E. ; Gianotti, F. ; Giarrusso, S. ; Giavitto, G. ; Giebels, B. ; Gika, V. ; Giommi, P. ; Girard, N. ; Giro, E. ; Giuliani, A. ; Glanzman, T. ; Glicenstein, J. -F. ; Godinovic, N. ; Golev, V. ; Gomez Berisso, M. ; Gomez-Ortega, J. ; Gonzalez, M. M. ; Gonzalez, A. ; Gonzalez, F. ; Gonzalez Munoz, A. ; Gothe, K. S. ; Gougerot, M. ; Graciani, R. ; Grandi, P. ; Granena, F. ; Granot, J. ; Grasseau, G. ; Gredig, R. ; Green, A. ; Greenshaw, T. ; Gregoire, T. ; Grimm, O. ; Grube, J. ; Grudzinska, M. ; Gruev, V. ; Gruenewald, S. ; Grygorczuk, J. ; Guarino, V. ; Gunji, S. ; Gyuk, G. ; Hadasch, D. ; Hagiwara, R. ; Hahn, J. ; Hakansson, N. ; Hallgren, A. ; Hamer Heras, N. ; Hara, S. ; Hardcastle, M. J. ; Harris, J. ; Hassan, T. ; Hatanaka, K. ; Haubold, T. ; Haupt, A. ; Hayakawa, T. ; Hayashida, M. ; Heller, R. ; Henault, F. ; Henri, G. ; Hermann, G. ; Hermel, R. ; Herrero, A. ; Hidaka, N. ; Hinton, J. ; Hoffmann, D. ; Hofmann, W. ; Hofverberg, P. ; Holder, J. ; Horns, D. ; Horville, D. ; Houles, J. ; Hrabovsky, M. ; Hrupec, D. ; Huan, H. ; Huber, B. ; Huet, J. -M. ; Hughes, G. ; Humensky, T. B. ; Huovelin, J. ; Ibarra, A. ; Illa, J. M. ; Impiombato, D. ; Incorvaia, S. ; Inoue, S. ; Inoue, Y. ; Ioka, K. ; Ismailova, E. ; Jablonski, C. ; Jacholkowska, A. ; Jamrozy, M. ; Janiak, M. ; Jean, P. ; Jeanney, C. ; Jimenez, J. J. ; Jogler, T. ; Johnson, T. ; Journet, L. ; Juffroy, C. ; Jung, I. ; Kaaret, P. ; Kabuki, S. ; Kagaya, M. ; Kakuwa, J. ; Kalkuhl, C. ; Kankanyan, R. ; Karastergiou, A. ; Kaercher, K. ; Karczewski, M. ; Karkar, S. ; Kasperek, Aci. ; Kastana, D. ; Katagiri, H. ; Kataoka, J. ; Katarzynski, K. ; Katz, U. ; Kawanaka, N. ; Kellner-Leidel, B. ; Kelly, H. ; Kendziorra, E. ; Khelifi, B. ; Kieda, D. B. ; Kifune, T. ; Kihm, T. ; Kishimoto, T. ; Kitamoto, K. ; Kluzniak, W. ; Knapic, C. ; Knapp, J. w ; Knoedlseder, J. ; Koeck, F. ; Kocot, J. ; Kodani, K. ; Koehne, J. -H. ; Kohri, K. ; Kokkotas, K. ; Kolitzus, D. ; Komin, N. ; Kominis, I. ; Konno, Y. ; Koeppel, H. ; Korohoda, P. ; Kosack, K. ; Koss, G. ; Kossakowski, R. ; Kostka, P. ; Koul, R. ; Kowal, G. ; Koyama, S. ; Koziol, J. ; Kraehenbuehl, T. ; Krause, J. ; Krawzcynski, H. ; Krennrich, F. ; Krepps, A. ; Kretzschmann, A. ; Krobot, R. ; Krueger, P. ; Kubo, H. ; Kudryavtsev, V. A. ; Kushida, J. ; Kuznetsov, A. ; La Barbera, A. ; La Palombara, N. ; La Parola, V. ; La Rosa, G. ; Lacombe, K. ; Lamanna, G. ; Lande, J. ; Languignon, D. ; Lapington, J. ; Laporte, P. ; Lavalley, C. ; Le Flour, T. ; Le Padellec, A. ; Lee, S. -H. ; Lee, W. H. ; Leigui de Oliveira, M. A. ; Lelas, D. ; Lenain, J. -P. ; Leopold, D. J. ; Lerch, T. ; Lessio, L. ; Lieunard, B. ; Lindfors, E. ; Liolios, A. ; Lipniacka, A. ; Lockart, H. ; Lohse, T. ; Lombardi, S. ; Lopatin, A. ; Lopez, M. ; Lopez-Coto, R. ; Lopez-Oramas, A. ; Lorca, A. ; Lorenz, E. ; Lubinski, P. ; Lucarelli, F. ; Luedecke, H. ; Ludwin, J. ; Luque-Escamilla, P. L. ; Lustermann, W. ; Luz, O. ; Lyard, E. ; Maccarone, M. C. ; Maccarone, T. J. ; Madejski, G. M. ; Madhavan, A. ; Mahabir, M. ; Maier, G. ; Majumdar, P. ; Malaguti, G. ; Maltezos, S. ; Manalaysay, A. ; Mancilla, A. ; Mandat, D. ; Maneva, G. ; Mangano, A. ; Manigot, P. ; Mannheim, K. ; Manthos, I. ; Maragos, N. ; Marcowith, A. ; Mariotti, M. ; Marisaldi, M. ; Markoff, S. ; Marszalek, A. ; Martens, C. ; Marti, J. ; Martin, J-M. ; Martin, P. ; Martinez, G. ; Martinez, F. ; Martinez, M. ; Masserot, A. ; Mastichiadis, A. ; Mathieu, A. ; Matsumoto, H. ; Mattana, F. ; Mattiazzo, S. ; Maurin, G. ; Maxfield, S. ; Maya, J. ; Mazin, D. ; Mc Comb, L. ; McCubbin, N. ; McHardy, I. ; McKay, R. ; Medina, C. ; Melioli, C. ; Melkumyan, D. ; Mereghetti, S. ; Mertsch, P. ; Meucci, M. ; Michalowski, J. ; Micolon, P. ; Mihailidis, A. ; Mineo, T. ; Minuti, M. ; Mirabal, N. ; Mirabel, F. ; Miranda, J. M. ; Mirzoyan, R. ; Mizuno, T. ; Moal, B. ; Moderski, R. ; Mognet, I. ; Molinari, E. ; Molinaro, M. ; Montaruli, T. ; Monteiro, I. ; Moore, P. ; Moralejo Olaizola, A. ; Mordalska, M. ; Morello, C. ; Mori, K. ; Mottez, F. ; Moudden, Y. ; Moulin, E. ; Mrusek, I. ; Mukherjee, R. ; Munar-Adrover, P. ; Muraishi, H. ; Murase, K. ; Murphy, A. ; Nagataki, S. ; Naito, T. ; Nakajima, D. ; Nakamori, T. ; Nakayama, K. ; Naumann, C. L. ; Naumann, D. ; Naumann-Godo, M. ; Nayman, P. ; Nedbal, D. ; Neise, D. ; Nellen, L. ; Neustroev, V. ; Neyroud, N. ; Nicastro, L. ; Nicolau-Kuklinski, J. ; Niedzwiecki, A. ; Niemiec, J. ; Nieto, D. ; Nikolaidis, A. ; Nishijima, K. ; Nolan, S. ; Northrop, R. ; Nosek, D. ; Nowak, N. ; Nozato, A. ; O'Brien, P. ; Ohira, Y. ; Ohishi, M. ; Ohm, S. ; Ohoka, H. ; Okuda, T. ; Okumura, A. ; Olive, J. -F. ; Ong, R. A. ; Orito, R. ; Orr, M. ; Osborne, J. ; Ostrowski, M. ; Otero, L. A. ; Otte, N. ; Ovcharov, E. ; Oya, I. ; Ozieblo, A. ; Padilla, L. ; Paiano, S. ; Paillot, D. ; Paizis, A. ; Palanque, S. ; Palatka, M. ; Pallota, J. ; Panagiotidis, K. ; Panazol, J. -L. ; Paneque, D. ; Panter, M. ; Paoletti, R. ; Papayannis, Alexandros ; Papyan, G. ; Paredes, J. M. ; Pareschi, G. ; Parks, G. ; Parraud, J. -M. ; Parsons, D. ; Arribas, M. Paz ; Pech, M. ; Pedaletti, G. ; Pelassa, V. ; Pelat, D. ; Perez, M. D. C. ; Persic, M. ; Petrucci, P-O ; Peyaud, B. ; Pichel, A. ; Pita, S. ; Pizzolato, F. ; Platos, L. ; Platzer, R. ; Pogosyan, L. ; Pohl, M. ; Pojmanski, G. ; Ponz, J. D. ; Potter, W. ; Poutanen, J. ; Prandini, E. ; Prast, J. ; Preece, R. ; Profeti, F. ; Prokoph, H. ; Prouza, M. ; Proyetti, M. ; Puerto-Gimenez, I. ; Puehlhofer, G. ; Puljak, I. ; Punch, M. ; Pyziol, R. ; Quel, E. J. ; Quinn, J. ; Quirrenbach, A. ; Racero, E. ; Rajda, P. J. ; Ramon, P. ; Rando, R. ; Rannot, R. C. ; Rataj, M. ; Raue, M. ; Reardon, P. ; Reimann, O. ; Reimer, A. ; Reimer, O. ; Reitberger, K. ; Renaud, M. ; Renner, S. ; Reville, B. ; Rhode, W. ; Ribo, M. ; Ribordy, M. ; Richer, M. G. ; Rico, J. ; Ridky, J. ; Rieger, F. ; Ringegni, P. ; Ripken, J. ; Ristori, P. R. ; Riviere, A. ; Rivoire, S. ; Rob, L. ; Roeser, U. ; Rohlfs, R. ; Rojas, G. ; Romano, Patrizia ; Romaszkan, W. ; Romero, G. E. ; Rosen, S. ; Lees, S. Rosier ; Ross, D. ; Rouaix, G. ; Rousselle, J. ; Rousselle, S. ; Rovero, A. C. ; Roy, F. ; Royer, S. ; Rudak, B. ; Rulten, C. ; Rupinski, M. ; Russo, F. ; Ryde, F. ; Sacco, B. ; Saemann, E. O. ; Saggion, A. ; Safiakian, V. ; Saito, K. ; Saito, T. ; Saito, Y. ; Sakaki, N. ; Sakonaka, R. ; Salini, A. ; Sanchez, F. ; Sanchez-Conde, M. ; Sandoval, A. ; Sandaker, H. ; Sant'Ambrogio, E. ; Santangelo, A. ; Santos, E. M. ; Sanuy, A. ; Sapozhnikov, L. ; Sarkar, S. ; Sartore, N. ; Sasaki, H. ; Satalecka, K. ; Sawada, M. ; Scalzotto, V. ; Scapin, V. ; Scarcioffolo, M. ; Schafer, J. ; Schanz, T. ; Schlenstedt, S. ; Schlickeiser, R. ; Schmidt, T. ; Schmoll, J. ; Schovanek, P. ; Schroedter, M. ; Schultz, C. ; Schultze, J. ; Schulz, A. ; Schure, K. ; Schwab, T. ; Schwanke, U. ; Schwarz, J. ; Schwarzburg, S. ; Schweizer, T. ; Schwemmer, S. ; Segreto, A. ; Seiradakis, J. -H. ; Sembroski, G. H. ; Seweryn, K. ; Sharma, M. ; Shayduk, M. ; Shellard, R. C. ; Shi, J. ; Shibata, T. ; Shibuya, A. ; Shum, E. ; Sidoli, L. ; Sidz, M. ; Sieiro, J. ; Sikora, M. ; Silk, J. ; Sillanpaa, A. ; Singh, B. B. ; Sitarek, J. ; Skole, C. ; Smareglia, R. ; Smith, A. ; Smith, D. ; Smith, J. ; Smith, N. ; Sobczynska, D. ; Sol, H. ; Sottile, G. ; Sowinski, M. ; Spanier, F. ; Spiga, D. ; Spyrou, S. ; Stamatescu, V. ; Stamerra, A. ; Starling, R. ; Stawarz, L. ; Steenkamp, R. ; Stegmann, Christian ; Steiner, S. ; Stergioulas, N. ; Sternberger, R. ; Sterzel, M. ; Stinzing, F. ; Stodulski, M. ; Straumann, U. ; Strazzeri, E. ; Stringhetti, L. ; Suarez, A. ; Suchenek, M. ; Sugawara, R. ; Sulanke, K. -H. ; Sun, S. ; Supanitsky, A. D. ; Suric, T. ; Sutcliffe, P. ; Sykes, J. ; Szanecki, M. ; Szepieniec, T. ; Szostek, A. ; Tagliaferri, G. ; Tajima, H. ; Takahashi, H. ; Takahashi, K. ; Takalo, L. ; Takami, H. ; Talbot, C. ; Tammi, J. ; Tanaka, M. ; Tanaka, S. ; Tasan, J. ; Tavani, M. ; Tavernet, J. -P. ; Tejedor, L. A. ; Telezhinsky, Igor O. ; Temnikov, P. ; Tenzer, C. ; Terada, Y. ; Terrier, R. ; Teshima, M. ; Testa, V. ; Tezier, D. ; Thuermann, D. ; Tibaldo, L. ; Tibolla, O. ; Tiengo, A. ; Tluczykont, M. ; Todero Peixoto, C. J. ; Tokanai, F. ; Tokarz, M. ; Toma, K. ; Torii, K. ; Tornikoski, M. ; Torres, D. F. ; Torres, M. ; Tosti, G. ; Totani, T. ; Toussenel, C. ; Tovmassian, G. ; Travnicek, P. ; Trifoglio, M. ; Troyano, I. ; Tsinganos, K. ; Ueno, H. ; Umehara, K. ; Upadhya, S. S. ; Usher, T. ; Uslenghi, M. ; Valdes-Galicia, J. F. ; Vallania, P. ; Vallejo, G. ; van Driel, W. ; van Eldik, C. ; Vandenbrouke, J. ; Vanderwalt, J. ; Vankov, H. ; Vasileiadis, G. ; Vassiliev, V. ; Veberic, D. ; Vegas, I. ; Vercellone, S. ; Vergani, S. ; Veyssiere, C. ; Vialle, J. P. ; Viana, A. ; Videla, M. ; Vincent, P. ; Vincent, S. ; Vink, J. ; Vlahakis, N. ; Vlahos, L. ; Vogler, P. ; Vollhardt, A. ; von Gunten, H. P. ; Vorobiov, S. ; Vuerli, C. ; Waegebaert, V. ; Wagner, R. ; Wagner, R. G. ; Wagner, S. ; Wakely, S. P. ; Walter, R. ; Walther, T. ; Warda, K. ; Warwick, R. ; Wawer, P. ; Wawrzaszek, R. ; Webb, N. ; Wegner, P. ; Weinstein, A. ; Weitzel, Q. ; Welsing, R. ; Werner, M. ; Wetteskind, H. ; White, R. ; Wierzcholska, A. ; Wiesand, S. ; Wilkinson, M. ; Williams, D. A. ; Willingale, R. ; Winiarski, K. ; Wischnewski, R. ; Wisniewski, L. ; Wood, M. ; Woernlein, A. ; Xiong, Q. ; Yadav, K. K. ; Yamamoto, H. ; Yamamoto, T. ; Yamazaki, R. ; Yanagita, S. ; Yebras, J. M. ; Yelos, D. ; Yoshida, A. ; Yoshida, T. ; Yoshikoshi, T. ; Zabalza, V. ; Zacharias, M. ; Zajczyk, A. ; Zanin, R. ; Zdziarski, A. ; Zech, Alraune ; Zhao, A. ; Zhou, X. ; Zietara, K. ; Ziolkowski, J. ; Ziolkowski, P. ; Zitelli, V. ; Zurbach, C. ; Zychowski, P.
The Cherenkov Telescope Array (CTA) is a new observatory for very high-energy (VHE) gamma rays. CTA has ambitions science goals, for which it is necessary to achieve full-sky coverage, to improve the sensitivity by about an order of magnitude, to span about four decades of energy, from a few tens of GeV to above 100 TeV with enhanced angular and energy resolutions over existing VHE gamma-ray observatories. An international collaboration has formed with more than 1000 members from 27 countries in Europe, Asia, Africa and North and South America. In 2010 the CTA Consortium completed a Design Study and started a three-year Preparatory Phase which leads to production readiness of CTA in 2014. In this paper we introduce the science goals and the concept of CTA, and provide an overview of the project.
Aliu, E. ; Archambault, S. ; Archer, A. ; Arlen, T. ; Aune, T. ; Barnacka, Anna ; Behera, B. ; Beilicke, M. ; Benbow, W. ; Berger, K. ; Bird, R. ; Böttcher, Markus ; Bouvier, A. ; Buchovecky, M. ; Buckley, J. H. ; Bugaev, V. ; Cardenzana, J. V. ; Cerruti, M. ; Cesarini, A. ; Chen, Xuhui ; Ciupik, L. ; Collins-Hughes, E. ; Connolly, M. P. ; Cui, W. ; Dumm, J. ; Eisch, J. D. ; Falcone, A. ; Federici, Simone ; Feng, Q. ; Finley, J. P. ; Fleischhack, H. ; Fortin, P. ; Fortson, L. ; Furniss, A. ; Galante, N. ; Gall, D. ; Gillanders, G. H. ; Griffin, S. ; Griffiths, S. T. ; Grube, J. ; Gyuk, G. ; Hütten, M. ; Hakansson, Nils ; Holder, J. ; Hughes, G. ; Humensky, T. B. ; Johnson, C. A. ; Kaaret, P. ; Kar, P. ; Kelley-Hoskins, N. ; Kertzman, M. ; Khassen, Y. ; Kieda, D. ; Krause, M. ; Krawczynski, H. ; Krennrich, F. ; Lang, M. J. ; Madhavan, A. S. ; Maier, G. ; McArthur, S. ; McCann, A. ; Meagher, K. ; Millis, J. ; Moriarty, P. ; Mukherjee, R. ; Nieto, D. ; Ong, R. A. ; Orr, M. ; Otte, A. N. ; Pandel, D. ; Park, N. ; Pelassa, V. ; Perkins, J. S. ; Pichel, A. ; Pohl, Martin ; Popkow, A. ; Quinn, J. ; Ragan, K. ; Reyes, L. C. ; Reynolds, P. T. ; Roache, E. ; Rousselle, J. ; Rovero, A. C. ; Saxon, D. B. ; Sembroski, G. H. ; Shahinyan, K. ; Sheidaei, F. ; Skole, C. ; Smith, A. W. ; Staszak, D. ; Telezhinsky, Igor O. ; Theiling, M. ; Todd, N. W. ; Tucci, J. V. ; Tyler, J. ; Varlotta, A. ; Vassiliev, V. V. ; Vincent, S. ; Wakely, S. P. ; Weiner, O. M. ; Weinstein, A. ; Welsing, R. ; Wilhelm, Alina ; Williams, D. A. ; Zitzer, B. ; Baring, M. G. ; Gonzalez, J. Becerra ; Cillis, A. N. ; Horan, D. ; Paneque, D.
The very high energy (VHE; E > 100 GeV) blazar Markarian 501 was observed between April 17 and May 5 (MJD 54 938-54 956), 2009, as part of an extensive multiwavelength campaign from radio to VHE. Strong VHE yray activity was detected on May 1st with Whipple and VERITAS, when the flux (E > 400 GeV) increased to 10 times the preflare baseline flux (3.9 x 10(-11) ph cm(-2) s(-1)), reaching five times the flux of the Crab Nebula. This coincided with a decrease in the optical polarization and a rotation of the polarization angle by 15. This VHE flare showed a fast flux variation with an increase of a factor similar to 4 in 25 min, and a falling time of similar to 50 min. We present the observations of the quiescent state previous to the flare and of the high state after the flare, focusing on the flux and spectral variability from Whipple, VERITAS, Fermi-LAT, RXTE, and Swift combined with optical and radio data.
Dark matter constraints from a joint analysis of dwarf Spheroidal galaxy observations with VERITAS
(2017)
Archambault, S. ; Archer, A. ; Benbow, W. ; Bird, R. ; Bourbeau, E. ; Brantseg, T. ; Buchovecky, M. ; Buckley, J. H. ; Bugaev, V. ; Byrum, K. ; Cerruti, M. ; Christiansen, J. L. ; Connolly, M. P. ; Cui, W. ; Daniel, M. K. ; Feng, Q. ; Finley, J. P. ; Fleischhack, H. ; Fortson, L. ; Furniss, A. ; Geringer-Sameth, A. ; Griffin, S. ; Grube, J. ; Hütten, M. ; Hakansson, N. ; Hanna, D. ; Hervet, O. ; Holder, J. ; Hughes, G. ; Hummensky, B. ; Johnson, C. A. ; Kaaret, P. ; Kar, P. ; Kelley-Hoskins, N. ; Kertzman, M. ; Kieda, D. ; Koushiappas, S. ; Krause, M. ; Krennrich, F. ; Lang, M. J. ; Lin, T. T. Y. ; McArthur, S. ; Moriarty, P. ; Mukherjee, R. ; Nieto, D. ; Ong, R. A. ; Otte, A. N. ; Park, N. ; Pohl, M. ; Popkow, A. ; Pueschel, Elisa ; Quinn, J. ; Ragan, K. ; Reynolds, P. T. ; Richards, G. T. ; Roache, E. ; Rulten, C. ; Sadeh, I. ; Santander, M. ; Sembroski, G. H. ; Shahinyan, K. ; Smith, A. W. ; Staszak, D. ; Telezhinsky, Igor O. ; Trepanier, S. ; Tucci, J. V. ; Tyler, J. ; Wakely, S. P. ; Weinstein, A. ; Wilcox, P. ; Williams, D. A. ; Zitzer, B.
We present constraints on the annihilation cross section of weakly interacting massive particles dark matter based on the joint statistical analysis of four dwarf galaxies with VERITAS. These results are derived from an optimized photon weighting statistical technique that improves on standard imaging atmospheric Cherenkov telescope (IACT) analyses by utilizing the spectral and spatial properties of individual photon events. We report on the results of similar to 230 hours of observations of five dwarf galaxies and the joint statistical analysis of four of the dwarf galaxies. We find no evidence of gamma-ray emission from any individual dwarf nor in the joint analysis. The derived upper limit on the dark matter annihilation cross section from the joint analysis is 1.35 x 10(-23) cm(3) s(-1) at 1 TeV for the bottom quark (b (b) over bar) final state, 2.85 x 10(-24) cm(3) s(-1) at 1 TeV for the tau lepton (tau+tau(-)) final state and 1.32 x 10-25 cm(3) s(-1) at 1 TeV for the gauge boson (gamma gamma) final state.
Aliu, E. ; Archambault, S. ; Arlen, T. ; Aune, T. ; Barnacka, Anna ; Beilicke, M. ; Benbow, W. ; Berger, K. ; Bird, R. ; Bouvier, A. ; Buckley, J. H. ; Bugaev, V. ; Cerruti, M. ; Chen, X. ; Ciupik, L. ; Collins-Hughes, E. ; Connolly, M. P. ; Cui, W. ; Dumm, J. ; Eisch, J. D. ; Falcone, A. ; Federici, S. ; Feng, Q. ; Finley, J. P. ; Fleischhack, H. ; Fortin, P. ; Fortson, L. ; Furniss, A. ; Galante, N. ; Gillanders, G. H. ; Griffin, S. ; Griffiths, S. T. ; Grube, J. ; Gyuk, G. ; Hakansson, N. ; Hanna, D. ; Holder, J. ; Hughes, G. ; Hughes, Z. ; Humensky, T. B. ; Johnson, C. A. ; Kaaret, P. ; Kar, P. ; Kertzman, M. ; Khassen, Y. ; Kieda, D. ; Krawczynski, H. ; Krennrich, F. ; Lang, M. J. ; Madhavan, A. S. ; Majumdar, P. ; McArthur, S. ; McCann, A. ; Meagher, K. ; Millis, J. ; Moriarty, P. ; Mukherjee, R. ; Nelson, T. ; Nieto, D. ; Ong, R. A. ; Otte, A. N. ; Park, N. ; Perkins, J. S. ; Pohl, M. ; Popkow, A. ; Prokoph, H. ; Quinn, J. ; Ragan, K. ; Rajotte, J. ; Reyes, L. C. ; Reynolds, P. T. ; Richards, G. T. ; Roache, E. ; Sadun, A. ; Santander, M. ; Sembroski, G. H. ; Shahinyan, K. ; Sheidaei, F. ; Smith, A. W. ; Staszak, D. ; Telezhinsky, Igor O. ; Theiling, M. ; Tyler, J. ; Varlotta, A. ; Vassiliev, V. V. ; Vincent, S. ; Wakely, S. P. ; Weekes, T. C. ; Weinstein, A. ; Welsing, R. ; Wilhelm, Alina ; Williams, D. A. ; Zitzer, B. ; Boettcher, Markus ; Fumagalli, M.
We summarize broadband observations of the TeV-emitting blazar 1ES 1959+650, including optical R-band observations by the robotic telescopes Super-LOTIS and iTelescope, UV observations by Swift Ultraviolet and Optical Telescope, X-ray observations by the Swift X-ray Telescope, high-energy gamma-ray observations with the Fermi Large Area Telescope, and very-high-energy (VHE) gamma-ray observations by VERITAS above 315 GeV, all taken between 2012 April 17 and 2012 June 1 (MJD 56034 and 56079). The contemporaneous variability of the broadband spectral energy distribution is explored in the context of a simple synchrotron self Compton (SSC) model. In the SSC emission scenario, we find that the parameters required to represent the high state are significantly different than those in the low state. Motivated by possible evidence of gas in the vicinity of the blazar, we also investigate a reflected emission model to describe the observed variability pattern. This model assumes that the non-thermal emission from the jet is reflected by a nearby cloud of gas, allowing the reflected emission to re-enter the blob and produce an elevated gamma-ray state with no simultaneous elevated synchrotron flux. The model applied here, although not required to explain the observed variability pattern, represents one possible scenario which can describe the observations. As applied to an elevated VHE state of 66% of the Crab Nebula flux, observed on a single night during the observation period, the reflected emission scenario does not support a purely leptonic non-thermal emission mechanism. The reflected emission model does, however, predict a reflected photon field with sufficient energy to enable elevated gamma-ray emission via pion production with protons of energies between 10 and 100 TeV.
Allen, C. ; Archambault, S. ; Archer, A. ; Benbow, W. ; Bird, R. ; Bourbeau, E. ; Brose, Robert ; Buchovecky, M. ; Buckley, J. H. ; Bugaev, V. ; Cardenzana, J. V. ; Cerruti, M. ; Chen, Xuhui ; Christiansen, J. L. ; Connolly, M. P. ; Cui, W. ; Daniel, M. K. ; Eisch, J. D. ; Falcone, Abe ; Feng, Q. ; Fernandez-Alonso, M. ; Finley, J. P. ; Fleischhack, H. ; Flinders, A. ; Fortson, L. ; Furniss, A. ; Gillanders, G. H. ; Griffin, S. ; Grube, J. ; Huetten, M. ; Hakansson, N. ; Hanna, D. ; Hervet, O. ; Holder, J. ; Hughes, G. ; Humensky, T. B. ; Johnson, C. A. ; Kaaret, P. ; Kar, P. ; Kelley-Hoskins, N. ; Kertzman, M. ; Kieda, D. ; Krause, M. ; Krennrich, F. ; Kumar, S. ; Lang, M. J. ; Maier, G. ; McArthur, S. ; McCann, A. ; Meagher, K. ; Moriarty, P. ; Mukherjee, R. ; Nguyen, T. ; Nieto, D. ; Ong, R. A. ; Otte, A. N. ; Park, N. ; Petrashyk, A. ; Pichel, A. ; Pohl, Martin ; Popkow, A. ; Pueschel, Elisa ; Quinn, J. ; Ragan, K. ; Reynolds, P. T. ; Richards, G. T. ; Roache, E. ; Rovero, A. C. ; Rulten, C. ; Sadeh, I. ; Santander, Marcos ; Sembroski, G. H. ; Shahinyan, K. ; Telezhinsky, Igor O. ; Tucci, J. V. ; Tyler, J. ; Wakely, S. P. ; Weinstein, A. ; Wilhelm, Alina ; Williams, D. A.
We present very-high-energy gamma-ray observations of the BL Lac object 1ES 2344+514 taken by the Very Energetic Radiation Imaging Telescope Array System between 2007 and 2015. 1ES 2344+514 is detected with a statistical significance above the background of 20.8 sigma in 47.2 h (livetime) of observations, making this the most comprehensive very-high-energy study of 1ES 2344+514 to date. Using these observations, the temporal properties of 1ES 2344+514 are studied on short and long times-scales. We fit a constant-flux model to nightly and seasonally binned light curves and apply a fractional variability test to determine the stability of the source on different time-scales. We reject the constant-flux model for the 2007-2008 and 2014-2015 nightly binned light curves and for the long-term seasonally binned light curve at the > 3 sigma level. The spectra of the time-averaged emission before and after correction for attenuation by the extragalactic background light are obtained. The observed time-averaged spectrum above 200 GeV is satisfactorily fitted (x(2)/NDF = 7.89/6) by a power-law function with an index Gamma = 2.46 +/- 0.06(stat) +/- 0.20(sys) and extends to at least 8 TeV. The extragalactic-backgroundlight-deabsorbed spectrum is adequately fit (x(2)/NDF = 6.73/6) by a power-law function with an index Gamma = 2.15 +/- 0.06(stat) +/- 0.20(sys) while an F-test indicates that the power law with an exponential cut-off function provides a marginally better fit (x(2)/NDF = 2.56/5) at the 2.1 sigma level. The source location is found to be consistent with the published radio location and its spatial extent is consistent with a point source.
Furniss, A. ; Noda, K. ; Boggs, S. ; Chiang, J. ; Christensen, F. ; Craig, W. ; Giommi, P. ; Hailey, C. ; Harisson, F. ; Madejski, G. ; Nalewajko, K. ; Perri, M. ; Stern, D. ; Urry, M. ; Verrecchia, F. ; Zhang, W. ; Ahnen, M. L. ; Ansoldi, S. ; Antonelli, L. A. ; Antoranz, P. ; Babic, A. ; Banerjee, B. ; Bangale, P. ; de Almeida, U. Barres ; Barrio, J. A. ; Becerra Gonzalez, J. ; Bednarek, W. ; Bernardini, E. ; Biasuzzi, B. ; Biland, A. ; Blanch Bigas, O. ; Bonnefoy, S. ; Bonnoli, G. ; Borracci, F. ; Bretz, T. ; Carmona, E. ; Carosi, A. ; Chatterjee, A. ; Clavero, R. ; Colin, P. ; Colombo, E. ; Contreras, J. L. ; Cortina, J. ; Covino, S. ; Da Vela, P. ; Dazzi, F. ; De Angelis, A. ; De Caneva, G. ; De Lotto, B. ; de Ona Wilhelmi, E. ; Delgado Mendez, C. ; Di Pierro, F. ; Prester, Dijana Dominis ; Dorner, D. ; Doro, M. ; Einecke, S. ; Eisenacher Glawion, D. ; Elsaesser, D. ; Fernandez-Barral, A. ; Fidalgo, D. ; Fonseca, M. V. ; Font, L. ; Frantzen, K. ; Fruck, C. ; Galindo, D. ; Garcia Lopez, R. J. ; Garczarczyk, M. ; Garrido Terrats, D. ; Gaug, M. ; Giammaria, P. ; Godinovic, N. ; Gonzalez Munoz, A. ; Guberman, D. ; Hanabata, Y. ; Hayashida, M. ; Herrera, J. ; Hose, J. ; Hrupec, D. ; Hughes, G. ; Idec, W. ; Kellermann, H. ; Kodani, K. ; Konno, Y. ; Kubo, H. ; Kushida, J. ; La Barbera, A. ; Lelas, D. ; Lewandowska, N. ; Lindfors, E. ; Lombardi, S. ; Longo, F. ; Lopez, M. ; Lopez-Coto, R. ; Lopez-Oramas, A. ; Lorenz, E. ; Majumdar, P. ; Makariev, M. ; Mallot, K. ; Maneva, G. ; Manganaro, M. ; Mannheim, K. ; Maraschi, L. ; Marcote, B. ; Mariotti, M. ; Martinez, M. ; Mazin, D. ; Menzel, U. ; Miranda, J. M. ; Mirzoyan, R. ; Moralejo, A. ; Nakajima, D. ; Neustroev, V. ; Niedzwiecki, A. ; Nievas Rosillo, M. ; Nilsson, K. ; Nishijima, K. ; Orito, R. ; Overkemping, A. ; Paiano, S. ; Palacio, J. ; Palatiello, M. ; Paneque, D. ; Paoletti, R. ; Paredes, J. M. ; Paredes-Fortuny, X. ; Persic, M. ; Poutanen, J. ; Moroni, P. G. Prada ; Prandini, E. ; Puljak, I. ; Reinthal, R. ; Rhode, W. ; Ribo, M. ; Rico, J. ; Garcia, J. Rodriguez ; Saito, T. ; Saito, K. ; Satalecka, K. ; Scapin, V. ; Schultz, C. ; Schweizer, T. ; Shore, S. N. ; Sillanpaa, A. ; Sitarek, J. ; Snidaric, I. ; Sobczynska, D. ; Stamerra, A. ; Steinbring, T. ; Strzys, M. ; Takalo, L. ; Takami, H. ; Tavecchio, F. ; Temnikov, P. ; Terzic, T. ; Tescaro, D. ; Teshima, M. ; Thaele, J. ; Torres, D. F. ; Toyama, T. ; Treves, A. ; Verguilov, V. ; Vovk, I. ; Will, M. ; Zanin, R. ; Archer, A. ; Benbow, W. ; Bird, R. ; Biteau, Jonathan ; Bugaev, V. ; Cardenzana, J. V. ; Cerruti, M. ; Chen, Xuhui ; Ciupik, L. ; Connolly, M. P. ; Cui, W. ; Dickinson, H. J. ; Dumm, J. ; Eisch, J. D. ; Falcone, A. ; Feng, Q. ; Finley, J. P. ; Fleischhack, H. ; Fortin, P. ; Fortson, L. ; Gerard, L. ; Gillanders, G. H. ; Griffin, S. ; Griffiths, S. T. ; Grube, J. ; Gyuk, G. ; Hakansson, Nils ; Holder, J. ; Humensky, T. B. ; Johnson, C. A. ; Kaaret, P. ; Kertzman, M. ; Kieda, D. ; Krause, M. ; Krennrich, F. ; Lang, M. J. ; Lin, T. T. Y. ; Maier, G. ; McArthur, S. ; McCann, A. ; Meagher, K. ; Moriarty, P. ; Mukherjee, R. ; Nieto, D. ; Ong, R. A. ; Park, N. ; Petry, D. ; Pohl, Martin ; Popkow, A. ; Ragan, K. ; Ratliff, G. ; Reyes, L. C. ; Reynolds, P. T. ; Richards, G. T. ; Roache, E. ; Santander, M. ; Sembroski, G. H. ; Shahinyan, K. ; Staszak, D. ; Telezhinsky, Igor O. ; Tucci, J. V. ; Tyler, J. ; Vassiliev, V. V. ; Wakely, S. P. ; Weiner, O. M. ; Weinstein, A. ; Wilhelm, Alina ; Williams, D. A. ; Zitzer, B. ; Vince, O. ; Fuhrmann, L. ; Angelakis, E. ; Karamanavis, V. ; Myserlis, I. ; Krichbaum, T. P. ; Zensus, J. A. ; Ungerechts, H. ; Sievers, A. ; Bachev, R. ; Boettcher, Markus ; Chen, W. P. ; Damljanovic, G. ; Eswaraiah, C. ; Guver, T. ; Hovatta, T. ; Hughes, Z. ; Ibryamov, S. I. ; Joner, M. D. ; Jordan, B. ; Jorstad, S. G. ; Joshi, M. ; Kataoka, J. ; Kurtanidze, O. M. ; Kurtanidze, S. O. ; Lahteenmaki, A. ; Latev, G. ; Lin, H. C. ; Larionov, V. M. ; Mokrushina, A. A. ; Morozova, D. A. ; Nikolashvili, M. G. ; Raiteri, C. M. ; Ramakrishnan, V. ; Readhead, A. C. R. ; Sadun, A. C. ; Sigua, L. A. ; Semkov, E. H. ; Strigachev, A. ; Tammi, J. ; Tornikoski, M. ; Troitskaya, Y. V. ; Troitsky, I. S. ; Villata, M.
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.
Archambault, S. ; Archer, A. ; Benbow, W. ; Bird, R. ; Biteau, Jonathan ; Buchovecky, M. ; Buckley, J. H. ; Bugaev, V. ; Byrum, K. ; Cerruti, M. ; Chen, Xuhui ; Ciupik, L. ; Connolly, M. P. ; Cui, W. ; Eisch, J. D. ; Errando, M. ; Falcone, A. ; Feng, Q. ; Finley, J. P. ; Fleischhack, H. ; Fortin, P. ; Fortson, L. ; Furniss, A. ; Gillanders, G. H. ; Griffin, S. ; Grube, J. ; Gyuk, G. ; Huetten, M. ; Hakansson, Nils ; Hanna, D. ; Holder, J. ; Humensky, T. B. ; Johnson, C. A. ; Kaaret, P. ; Kar, P. ; Kelley-Hoskins, N. ; Kertzman, M. ; Kieda, D. ; Krause, M. ; Krennrich, F. ; Kumar, S. ; Lang, M. J. ; Maier, G. ; McArthur, S. ; McCann, A. ; Meagher, K. ; Moriarty, P. ; Mukherjee, R. ; Nguyen, T. ; Nieto, D. ; Ong, R. A. ; Otte, A. N. ; Park, N. ; Perkins, J. S. ; Pichel, A. ; Pohl, Martin ; Popkow, A. ; Pueschel, Elisa ; Quinn, J. ; Ragan, K. ; Reynolds, P. T. ; Richards, G. T. ; Roache, E. ; Rovero, A. C. ; Santander, M. ; Sembroski, G. H. ; Shahinyan, K. ; Smith, A. W. ; Staszak, D. ; Telezhinsky, Igor O. ; Tucci, J. V. ; Tyler, J. ; Vincent, S. ; Wakely, S. P. ; Weiner, O. M. ; Weinstein, A. ; Williams, D. A. ; Zitzer, B. ; Fumagalli, M. ; Prochaska, J. X.
Between the beginning of its full-scale scientific operations in 2007 and 2012, the VERITAS Cherenkov telescope array observed more than 130 blazars; of these, 26 were detected as very-high-energy (VHE; E > 100 GeV) gamma-ray sources. In this work, we present the analysis results of a sample of 114 undetected objects. The observations constitute a total live-time of similar to 570 hr. The sample includes several unidentified Fermi-Large Area Telescope (LAT) sources (located at high Galactic latitude) as well as all the sources from the second Fermi-LAT catalog that are contained within the field of view of the VERITAS observations. We have also performed optical spectroscopy measurements in order to estimate the redshift of some of these blazars that do not have spectroscopic distance estimates. We present new optical spectra from the Kast instrument on the Shane telescope at the Lick observatory for 18 blazars included in this work, which allowed for the successful measurement or constraint on the redshift of four of them. For each of the blazars included in our sample, we provide the flux upper limit in the VERITAS energy band. We also study the properties of the significance distributions and we present the result of a stacked analysis of the data set, which shows a 4s excess.
Aliu, E. ; Aune, T. ; Barnacka, Anna ; Beilicke, M. ; Benbow, W. ; Berger, K. ; Biteau, Jonathan ; Buckley, J. H. ; Bugaev, V. ; Byrum, K. ; Cardenzana, J. V. ; Cerruti, M. ; Chen, Xuhui ; Ciupik, L. ; Connaughton, V. ; Cui, W. ; Dickinson, H. J. ; Eisch, J. D. ; Errando, M. ; Falcone, A. ; Federici, Simone ; Feng, Q. ; Finley, J. P. ; Fleischhack, H. ; Fortin, P. ; Fortson, L. ; Furniss, A. ; Galante, N. ; Gillanders, G. H. ; Griffin, S. ; Griffiths, S. T. ; Grube, J. ; Gyuk, G. ; Hakansson, Nils ; Hanna, D. ; Holder, J. ; Hughes, G. ; Humensky, T. B. ; Johnson, C. A. ; Kaaret, P. ; Kar, P. ; Kertzman, M. ; Khassen, Y. ; Kieda, D. ; Krawczynski, H. ; Krennrich, F. ; Lang, M. J. ; Madhavan, A. S. ; Maier, G. ; McArthur, S. ; McCann, A. ; Meagher, K. ; Millis, J. ; Moriarty, P. ; Mukherjee, R. ; Nieto, D. ; Ong, R. A. ; Otte, A. N. ; Park, N. ; Pohl, Martin ; Popkow, A. ; Prokoph, H. ; Pueschel, Elisa ; Quinn, J. ; Ragan, K. ; Rajotte, J. ; Reyes, L. C. ; Reynolds, P. T. ; Richards, G. T. ; Roache, E. ; Sembroski, G. H. ; Shahinyan, K. ; Smith, A. W. ; Staszak, D. ; Telezhinsky, Igor O. ; Tucci, J. V. ; Tyler, J. ; Varlotta, A. ; Vassiliev, V. V. ; Vincent, S. ; Wakely, S. P. ; Weiner, O. M. ; Weinstein, A. ; Welsing, R. ; Wilhelm, Alina ; Williams, D. A. ; Zitzer, B. ; McEnery, J. E. ; Perkins, J. S. ; Veres, P. ; Zhu, S.
Prompt emission from the very fluent and nearby (z = 0.34) gamma-ray burst GRB130427A was detected by several orbiting telescopes and by ground-based, wide-field-of-view optical transient monitors. Apart from the intensity and proximity of this GRB, it is exceptional due to the extremely long-lived high-energy (100 MeV to 100 GeV) gamma-ray emission, which was detected by the Large Area Telescope on the Fermi Gamma-Ray Space Telescope for similar to 70 ks after the initial burst. The persistent, hard-spectrum, high-energy emission suggests that the highest-energy gamma rays may have been produced via synchrotron self-Compton processes though there is also evidence that the high-energy emission may instead be an extension of the synchrotron spectrum. VERITAS, a ground-based imaging atmospheric Cherenkov telescope array, began follow-up observations of GRB130427A similar to 71 ks (similar to 20 hr) after the onset of the burst. The GRB was not detected with VERITAS; however, the high elevation of the observations, coupled with the low redshift of the GRB, make VERITAS a very sensitive probe of the emission from GRB130427A for E > 100 GeV. The non-detection and consequent upper limit derived place constraints on the synchrotron self-Compton model of high-energy gamma-ray emission from this burst.
Aliu, E. ; Archer, A. ; Aune, T. ; Barnacka, Anna ; Behera, B. ; Beilicke, M. ; Benbow, W. ; Berger, K. ; Bird, R. ; Buckley, J. H. ; Bugaev, V. ; Byrum, K. ; Cardenzana, J. V. ; Cerruti, M. ; Chen, Xuhui ; Ciupik, L. ; Connolly, M. P. ; Cui, Wei ; Dickinson, H. J. ; Dumm, J. ; Eisch, J. D. ; Errando, M. ; Falcone, A. ; Federici, Simone ; Feng, Q. ; Finley, J. P. ; Fortin, P. ; Fortson, L. ; Furniss, A. ; Galante, N. ; Gillanders, G. H. ; Griffin, S. ; Griffiths, S. T. ; Grube, J. ; Gyuk, G. ; Hakansson, Nils ; Hanna, D. ; Holder, J. ; Hughes, G. ; Humensky, T. B. ; Johnson, C. A. ; Kaaret, P. ; Kar, P. ; Kertzman, M. ; Khassen, Y. ; Kieda, D. ; Krawczynski, H. ; Krennrich, F. ; Kumar, S. ; Lang, M. J. ; Madhavan, A. ; McArthur, S. ; McCann, A. ; Meagher, K. ; Millis, J. ; Moriarty, P. ; Nieto, Daniel ; Ong, R. A. ; Orr, M. ; Otte, A. N. ; Park, N. ; Perkins, J. S. ; Pohl, Martin ; Popkow, A. ; Prokoph, H. ; Pueschel, Elisa ; Quinn, J. ; Ragan, K. ; Rajotte, J. ; Reyes, L. C. ; Reynolds, P. T. ; Richards, G. T. ; Roache, E. ; Sembroski, G. H. ; Shahinyan, K. ; Staszak, D. ; Telezhinsky, Igor O. ; Tucci, J. V. ; Tyler, J. ; Varlotta, A. ; Vassiliev, V. V. ; Wakely, S. P. ; Weinstein, A. ; Welsing, R. ; Wilhelm, Alina ; Williams, D. A. ; Zitzer, B.
We present results from VERITAS observations of the BL Lac object PG 1553+113 spanning the years 2010, 2011, and 2012. The time-averaged spectrum, measured between 160 and 560 GeV, is well described by a power law with a spectral index of 4.33 +/- 0.09. The time-averaged integral flux above 200 GeV measured for this period was (1.69 +/- 0.06) x 10(-11) photons cm(-2) s(-1), corresponding to 6.9% of the Crab Nebula flux. We also present the combined gamma-ray spectrum from the Fermi Large Area Telescope and VERITAS covering an energy range from 100 MeV to 560 GeV. The data are well fit by a power law with an exponential cutoff at 101.9 +/- 3.2 GeV. The origin of the cutoff could be intrinsic to PG 1553+113 or be due to the gamma-ray opacity of our universe through pair production off the extragalactic background light (EBL). Given lower limits to the redshift of z > 0.395 based on optical/UV observations of PG 1553+113, the cutoff would be dominated by EBL absorption. Conversely, the small statistical uncertainties of the VERITAS energy spectrum have allowed us to provide a robust upper limit on the redshift of PG 1553+113 of z <= 0.62. A strongly elevated mean flux of (2.50 +/- 0.14) x10(-11) photons cm(-2) s(-1) (10.3% of the Crab Nebula flux) was observed during 2012, with the daily flux reaching as high as (4.44 +/- 0.71) x10(-11) photons cm(-2) s(-1) (18.3% of the Crab Nebula flux) on MJD 56048. The light curve measured during the 2012 observing season is marginally inconsistent with a steady flux, giving a chi(2) probability for a steady flux of 0.03%.
Archambault, S. ; Archer, A. ; Aune, T. ; Barnacka, Anna ; Benbow, W. ; Bird, R. ; Buchovecky, M. ; Buckley, J. H. ; Bugaev, V. ; Byrum, K. ; Cardenzana, J. V. ; Cerruti, M. ; Chen, Xuhui ; Ciupik, L. ; Collins-Hughes, E. ; Connolly, M. P. ; Cui, W. ; Dickinson, H. J. ; Dumm, J. ; Eisch, J. D. ; Falcone, A. ; Feng, Q. ; Finley, J. P. ; Fleischhack, H. ; Flinders, A. ; Fortin, P. ; Fortson, L. ; Furniss, A. ; Gillanders, G. H. ; Griffin, S. ; Grube, J. ; Gyuk, G. ; Huetten, M. ; Hakansson, Nils ; Hanna, D. ; Holder, J. ; Humensky, T. B. ; Johnson, C. A. ; Kaaret, P. ; Kar, P. ; Kelley-Hoskins, N. ; Kertzman, M. ; Khassen, Y. ; Kieda, D. ; Krause, M. ; Krennrich, F. ; Kumar, S. ; Lang, M. J. ; Maier, G. ; McArthur, S. ; McCann, A. ; Meagher, K. ; Millis, J. ; Moriarty, P. ; Mukherjee, R. ; Nieto, D. ; Ong, R. A. ; Otte, A. N. ; Pandel, D. ; Park, N. ; Pelassa, V. ; Pohl, Martin ; Popkow, A. ; Pueschel, Elisa ; Quinn, J. ; Ragan, K. ; Reynolds, P. T. ; Richards, G. T. ; Roache, E. ; Rousselle, J. ; Rulten, C. ; Santander, M. ; Sembroski, G. H. ; Shahinyan, K. ; Smith, A. W. ; Staszak, D. ; Telezhinsky, Igor O. ; Tucci, J. V. ; Tyler, J. ; Vincent, S. ; Wakely, S. P. ; Weiner, O. M. ; Weinstein, A. ; Wilhelm, Alina ; Williams, D. A. ; Zitzer, B.
The TeV binary system LS I +61 degrees 303 is known for its regular, non-thermal emission pattern that traces the orbital period of the compact object in its 26.5 day orbit around its B0 Ve star companion. The system typically presents elevated TeV emission around apastron passage with flux levels between 5% and 15% of the steady flux from the Crab Nebula (> 300 GeV). In this article, VERITAS observations of LS I + 61 degrees. 303 taken in late 2014 are presented, during which bright TeV flares around apastron at flux levels peaking above 30% of the Crab Nebula flux were detected. This is the brightest such activity from this source ever seen in the TeV regime. The strong outbursts have rise and fall times of less than a day. The short timescale of the flares, in conjunction with the observation of 10 TeV photons from LS I + 61 degrees 303 during the flares, provides constraints on the properties of the accelerator in the source.