1,877 results on '"Gall, D."'
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2. Electronic, optical and thermoelectric properties of sodium pnictogen chalcogenides: A first principles study
- Author
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Khare, I. S., Szymanski, N. J., Gall, D., and Irving, R. E.
- Subjects
Condensed Matter - Materials Science - Abstract
Ternary chalcogenides have been of recent investigation for applications in photovoltaic and thermoelectric devices. We study the structural, electronic, optical, and thermoelectric properties of nine ternary chalcogenides, NaAX$_{2}$, where A represents pnictogens (As, Sb, and Te) and X represents chalcogens (S, Se, and Te). Calculations based on density functional theory yield the following results: (i) phonon dispersion curves predict three of the compounds, NaAsS$_{2}$, NaSbS$_{2}$, and NaSbSe$_{2}$, to be dynamically stable in the monoclinic, C2/c, structure, (ii) the layered atomistic configuration causes the corresponding electronic and optical properties to display a high degree of anisotropy, (iii) A-X electronic bonding features vary significantly with structural distortions arising from atomic size mismatch, therefore directly influencing stability, (iv) strong absorption is observed in the stable compounds, with coefficients ranging from 10$^{4}$ to 10$^{5}$ cm$^{-1}$ in the visible-UV range, and (v) remarkably high Seebeck coefficients exceeding 500 ${\mu}$V/K at carrier concentrations commonly achieved in such materials. From these results, we conclude that NaAsS$_{2}$, NaSbS$_{2}$, and NaSbSe$_{2}$ are suitable candidates for both photovoltaic, particularly in tandem solar cells, and thermoelectric applications. Experimental synthesis and verification are suggested., Comment: Submitted to Computational Materials Science; 31 pages, 12 figures
- Published
- 2020
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3. Mechanical and electronic properties of transition metal hexa-nitrides in hexagonal structure from density functional theory calculations
- Author
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Kandel, S.R., Dumre, B.B., Gall, D., and Khare, S.V.
- Published
- 2023
- Full Text
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4. Investigation of hardness in transition metal hexa-nitrides in cubic structure: A first-principles study
- Author
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Kandel, S.R., Dumre, B.B., Gall, D., and Khare, S.V.
- Published
- 2022
- Full Text
- View/download PDF
5. Prediction of super hardness in transition metal hexa-nitrides from density functional theory computations
- Author
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Kandel, S.R., Dumre, B.B., Gall, D., and Khare, S.V.
- Published
- 2022
- Full Text
- View/download PDF
6. Correlating structure and orbital occupation with the stability and mechanical properties of 3d transition metal carbides
- Author
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Khatri, I., Szymanski, N.J., Dumre, B.B., Amar, J.G., Gall, D., and Khare, S.V.
- Published
- 2022
- Full Text
- View/download PDF
7. Cognitive emotion regulation questionnaire: Psychometric properties of the Tunisian version
- Author
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Ouerchefani, R., Ouerchefani, N., Ben Rejeb, M.R., and Le Gall, D.
- Published
- 2021
- Full Text
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8. Contributions of the Cherenkov Telescope Array (CTA) to the 6th International Symposium on High-Energy Gamma-Ray Astronomy (Gamma 2016)
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Consortium, The CTA, Abchiche, A., Abeysekara, U., Abril, Ó., Acero, F., Acharya, B. S., Adams, C., Agnetta, G., Aharonian, F., Akhperjanian, A., Albert, A., Alcubierre, M., Alfaro, J., Alfaro, R., Allafort, A. J., Aloisio, R., Amans, J. -P., Amato, E., Ambrogi, L., Ambrosi, G., Ambrosio, M., Anderson, J., Anduze, M., Angüner, E. O., Antolini, E., Antonelli, L. A., Antonucci, M., Antonuccio, V., Antoranz, P., Aramo, C., Aravantinos, A., Araya, M., Arcaro, C., Arezki, B., Argan, A., Armstrong, T., Arqueros, F., Arrabito, L., Arrieta, M., Asano, K., Ashley, M., Aubert, P., Singh, C. B., Babic, A., Backes, M., Bais, A., Bajtlik, S., Balazs, C., Balbo, M., Balis, D., Balkowski, C., Ballester, O., Ballet, J., Balzer, A., Bamba, A., Bandiera, R., Barber, A., Barbier, C., Barcelo, M., Barkov, M., Barnacka, A., de Almeida, U. Barres, Barrio, J. A., Basso, S., Bastieri, D., Bauer, C., Becciani, U., Becherini, Y., Tjus, J. Becker, Beckmann, V., Bednarek, W., Benbow, W., Ventura, D. Benedico, Berdugo, J., Berge, D., Bernardini, E., Bernardini, M. G., Bernhard, S., Bernlöhr, K., Bertucci, B., Besel, M. -A., Beshley, V., Bhatt, N., Bhattacharjee, P., Bhattacharyya, W., Bhattachryya, S., Biasuzzi, B., Bicknell, G., Bigongiari, C., Biland, A., Bilinsky, A., Bilnik, W., Biondo, B., Bird, R., Bird, T., Bissaldi, E., Bitossi, M., Blanch, O., Blasi, P., Blazek, J., Bockermann, C., Boehm, C., Bogacz, L., Bogdan, M., Bohacova, M., Boisson, C., Boix, J., Bolmont, J., Bonanno, G., Bonardi, A., Bonavolontà, C., Bonifacio, P., Bonnarel, F., Bonnoli, G., Borkowski, J., Bose, R., Bosnjak, Z., Böttcher, M., Bousquet, J. -J., Boutonnet, C., Bouyjou, F., Bowman, L., Braiding, C., Brantseg, T., Brau-Nogué, S., Bregeon, J., Briggs, M., Brigida, M., Bringmann, T., Brisken, W., Bristow, D., Britto, R., Brocato, E., Bron, S., Brook, P., Brooks, W., Brown, A. M., Brügge, K., Brun, F., Brun, P., Brunetti, G., Brunetti, L., Bruno, P., Buanes, T., Bucciantini, N., Buchholtz, G., Buckley, J., Bugaev, V., Bühler, R., Bulgarelli, A., Bulik, T., Burton, M., Burtovoi, A., Busetto, G., Buson, S., Buss, J., Byrum, K., Cadoux, F., Tovar, J. Calvo, Cameron, R., Canelli, F., Canestrari, R., Capalbi, M., Capasso, M., Capobianco, G., Caproni, A., Caraveo, P., Cardenzana, J., Cardillo, M., Carius, S., Carlile, C., Carosi, A., Carosi, R., Carquín, E., Carr, J., Carroll, M., Carter, J., Carton, P. -H., Casandjian, J. -M., Casanova, S., Cascone, E., Casiraghi, M., Castellina, A., Mora, J. Castroviejo, Catalani, F., Catalano, O., Catalanotti, S., Cauz, D., Cavazzani, S., Cerchiara, P., Chabanne, E., Chadwick, P., Chaleil, T., Champion, C., Chatterjee, A., Chaty, S., Chaves, R., Chen, A., Chen, X., Cheng, K., Chernyakova, M., Chiappetti, L., Chikawa, M., Chinn, D., Chitnis, V. R., Cho, N., Christov, A., Chudoba, J., Cieślar, M., Ciocci, M. A., Clay, R., Colafrancesco, S., Colin, P., Colley, J. -M., Colombo, E., Colome, J., Colonges, S., Conforti, V., Connaughton, V., Connell, S., Conrad, J., Contreras, J. L., Coppi, P., Corbel, S., Coridian, J., Cornat, R., Corona, P., Corti, D., Cortina, J., Cossio, L., Costa, A., Costantini, H., Cotter, G., Courty, B., Covino, S., Covone, G., Crimi, G., Criswell, S. J., Crocker, R., Croston, J., Cuadra, J., Cumani, P., Cusumano, G., Da Vela, P., Dale, Ø., D'Ammando, F., Dang, D., Dang, V. T., Dangeon, L., Daniel, M., Davids, I., Dawson, B., Dazzi, F., Costa, B. de Aguiar, De Angelis, A., Cardoso, R. F. de Araujo, De Caprio, V., Anjos, R. de Cássia dos, De Cesare, G., De Franco, A., De Frondat, F., Pino, E. M. de Gouveia Dal, de la Calle, I., De Lisio, C., Lopez, R. de los Reyes, De Lotto, B., De Luca, A., Neto, J. R. T. de Mello, de Naurois, M., Wilhelmi, E. de Oña, De Palma, F., De Persio, F., de Souza, V., Decock, G., Decock, J., Deil, C., Del Santo, M., Delagnes, E., Deleglise, G., Delgado, C., Delgado, J., della Volpe, D., Deloye, P., Detournay, M., Dettlaff, A., Devin, J., Di Girolamo, T., Di Giulio, C., Di Paola, A., Di Pierro, F., Diaz, M. A., Díaz, C., Dib, C., Dick, J., Dickinson, H., Diebold, S., Digel, S., Dipold, J., Disset, G., Distefano, A., Djannati-Ataï, A., Doert, M., Dohmke, M., Domínguez, A., Dominik, N., Dominique, J. -L., Prester, D. Dominis, Donat, A., Donnarumma, I., Dorner, D., Doro, M., Dournaux, J. -L., Downes, T., Doyle, K., Drake, G., Drappeau, S., Drass, H., Dravins, D., Drury, L., Dubus, G., Ducci, L., Dumas, D., Morå, K. Dundas, Durand, D., D'Urso, D., Dwarkadas, V., Dyks, J., Dyrda, M., Ebr, J., Edy, E., Egberts, K., Eger, P., Egorov, A., Einecke, S., Eisch, J., Eisenkolb, F., Eleftheriadis, C., Elsaesser, D., Elsässer, D., Emmanoulopoulos, D., Engelbrecht, C., Engelhaupt, D., Ernenwein, J. -P., Escarate, P., Eschbach, S., Espinoza, C., Evans, P., Fairbairn, M., Falceta-Goncalves, D., Falcone, A., Ramazani, V. Fallah, Fantinel, D., Farakos, K., Farnier, C., Farrell, E., Fasola, G., Favre, Y., Fede, E., Fedora, R., Fedorova, E., Fegan, S., Ferenc, D., Fernandez-Alonso, M., Fernández-Barral, A., Ferrand, G., Ferreira, O., Fesquet, M., Fetfatzis, P., Fiandrini, E., Fiasson, A., Filipčič, A., Filipovic, M., Fink, D., Finley, C., Finley, J. P., Finoguenov, A., Fioretti, V., Fiorini, M., Fleischhack, H., Flores, H., Florin, D., Föhr, C., Fokitis, E., Fonseca, M. V., Font, L., Fontaine, G., Fontes, B., Fornasa, M., Förster, A., Fortin, P., Fortson, L., Fouque, N., Franckowiak, A., Franco, F. J., Albuquerque, I. Freire Mota, Coromina, L. Freixas, Fresnillo, L., Fruck, C., Fuessling, M., Fugazza, D., Fujita, Y., Fukami, S., Fukazawa, Y., Fukuda, T., Fukui, Y., Funk, S., Furniss, A., Gäbele, W., Gabici, S., Gadola, A., Galindo, D., Gall, D. D., Gallant, Y., Galloway, D., Gallozzi, S., Galvez, J. A., Gao, S., Garcia, A., Garcia, B., Gil, R. García, López, R. Garcia, Garczarczyk, M., Gardiol, D., Gargano, C., Gargano, F., Garozzo, S., Garrecht, F., Garrido, L., Garrido-Ruiz, M., Gascon, D., Gaskins, J., Gaudemard, J., Gaug, M., Gaweda, J., Gebhardt, B., Gebyehu, M., Geffroy, N., Genolini, B., Gerard, L., Ghalumyan, A., Ghedina, A., Ghislain, P., Giammaria, P., Giannakaki, E., Gianotti, F., Giarrusso, S., Giavitto, G., Giebels, B., Gieras, T., Giglietto, N., Gika, V., Gimenes, R., Giomi, M., Giommi, P., Giordano, F., Giovannini, G., Girardot, P., Giro, E., Giroletti, M., Gironnet, J., Giuliani, A., Glicenstein, J. -F., Gnatyk, R., Godinovic, N., Goldoni, P., Gomez, G., Gonzalez, M. M., González, A., Gora, D., Gothe, K. S., Gotz, D., Goullon, J., Grabarczyk, T., Graciani, R., Graham, J., Grandi, P., Granot, J., Grasseau, G., Gredig, R., Green, A. J., Green, A. M., Greenshaw, T., Grenier, I., Griffiths, S., Grillo, A., Grondin, M. -H., Grube, J., Grudzinska, M., Grygorczuk, J., Guarino, V., Guberman, D., Gunji, S., Gyuk, G., Hadasch, D., Hagedorn, A., Hagge, L., Hahn, J., Hakobyan, H., Hara, S., Hardcastle, M. J., Hassan, T., Hatanaka, K., Haubold, T., Haupt, A., Hayakawa, T., Hayashida, M., Heller, M., Heller, R., Helo, J. C., Henault, F., Henri, G., Hermann, G., Hermel, R., Llorente, J. Herrera, Herrero, A., Hervet, O., Hidaka, N., Hinton, J., Hirai, W., Hirotani, K., Hnatyk, B., Hoang, J., Hoffmann, D., Hofmann, W., Holch, T., Holder, J., Hooper, S., Horan, D., Hörandel, J., Hörbe, M., Horns, D., Horvath, P., Hose, J., Houles, J., Hovatta, T., Hrabovsky, M., Hrupec, D., Huet, J. -M., Huetten, M., Hughes, G., Hui, D., Humensky, T. B., Hussein, M., Iacovacci, M., Ibarra, A., Ikeno, Y., Illa, J. M., Impiombato, D., Inada, T., Incorvaia, S., Infante, L., Inome, Y., Inoue, S., Inoue, T., Inoue, Y., Iocco, F., Ioka, K., Iori, M., Ishio, K., Israel, G. L., Iwamura, Y., Jablonski, C., Jacholkowska, A., Jacquemier, J., Jamrozy, M., Janecek, P., Janiak, M., Jankowsky, D., Jankowsky, F., Jean, P., Jegouzo, I., Jenke, P., Jimenez, J. J., Jingo, M., Jocou, L., Jogler, T., Johnson, C. A., Jones, M., Josselin, M., Journet, L., Jung, I., Kaaret, P., Kagaya, M., Kakuwa, J., Kalekin, O., Kalkuhl, C., Kamon, H., Kankanyan, R., Karastergiou, A., Kärcher, K., Karczewski, M., Karkar, S., Karn, P., Kasperek, J., Katagiri, H., Kataoka, J., Katarzyński, K., Kato, S., Katz, U., Kawanaka, N., Kaye, L., Kazanas, D., Kelley-Hoskins, N., Kersten, J., Khélifi, B., Kieda, D. B., Kihm, T., Kimeswenger, S., Kisaka, S., Kishida, S., Kissmann, R., Klepser, S., Kluźniak, W., Knapen, J., Knapp, J., Knödlseder, J., Koch, B., Köck, F., Kocot, J., Kohri, K., Kokkotas, K., Kolitzus, D., Komin, N., Kominis, I., Kong, A., Konno, Y., Kosack, K., Koss, G., Kossatz, M., Kowal, G., Koyama, S., Kozioł, J., Kraus, M., Krause, J., Krause, M., Krawzcynski, H., Krennrich, F., Kretzschmann, A., Kruger, P., Kubo, H., Kudryavtsev, V., Mezek, G. Kukec, Kuklis, M., Kuroda, H., Kushida, J., La Barbera, A., La Palombara, N., La Parola, V., La Rosa, G., Laffon, H., Lahmann, R., Lakicevic, M., Lalik, K., Lamanna, G., Landriu, D., Landt, H., Lang, R. G., Lapington, J., Laporte, P., Fèvre, J. -P. Le, Flour, T. Le, Sidaner, P. Le, Lee, S. -H., Lee, W. H., Lees, J. -P., Lefaucheur, J., Leffhalm, K., Leich, H., de Oliveira, M. A. Leigui, Lelas, D., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Leonard, R., Leoni, R., Lessio, L., Leto, G., Leveque, A., Lieunard, B., Limon, M., Lindemann, R., Lindfors, E., Linhoff, L., Liolios, A., Lipniacka, A., Lockart, H., Lohse, T., Łokas, E., Lombardi, S., Longo, F., Lopatin, A., Lopez, M., Loreggia, D., Louge, T., Louis, F., Louys, M., Lucarelli, F., Lucchesi, D., Lüdecke, H., Luigi, T., Luque-Escamilla, P. L., Lyard, E., Maccarone, M. C., Maccarone, T., Maccarone, T. J., Mach, E., Madejski, G. M., Madonna, A., Magniette, F., Magniez, A., Mahabir, M., Maier, G., Majumdar, P., Makariev, M., Malaguti, G., Malaspina, G., Mallot, A. K., Malouf, A., Maltezos, S., Malyshev, D., Mancilla, A., Mandat, D., Maneva, G., Manganaro, M., Mangano, S., Manigot, P., Mankushiyil, N., Mannheim, K., Maragos, N., Marano, D., Marchegiani, P., Marcomini, J. 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M., Mirzoyan, R., Mitchell, A., Mizuno, T., Moderski, R., Mognet, I., Mohammed, M., Moharana, R., Mohrmann, L., Molinari, E., Molyneux, P., Monmarthe, E., Monnier, G., Montaruli, T., Monte, C., Monteiro, I., Mooney, D., Moore, P., Moralejo, A., Morello, C., Moretti, E., Mori, K., Morris, P., Morselli, A., Moscato, F., Motohashi, D., Mottez, F., Moudden, Y., Moulin, E., Mueller, S., Mukherjee, R., Munar, P., Munari, M., Mundell, C., Mundet, J., Muraishi, H., Murase, K., Muronga, A., Murphy, A., Nagar, N., Nagataki, S., Nagayoshi, T., Nagesh, B. K., Naito, T., Nakajima, D., Nakamori, T., Nakayama, K., Nanni, J., Naumann, D., Nayman, P., Nellen, L., Nemmen, R., Neronov, A., Neyroud, N., Nguyen, T., Nguyen, T. T., Trung, T. Nguyen, Nicastro, L., Nicolau-Kukliński, J., Niederwanger, F., Niedźwiecki, A., Niemiec, J., Nieto, D., Nievas-Rosillo, M., Nikolaidis, A., Nikołajuk, M., Nishijima, K., Nishikawa, K. -I., Nishiyama, G., Noda, K., Nogues, L., Nolan, S., Northrop, R., Nosek, D., Nöthe, M., Novosyadlyj, B., Nozka, L., Nunio, F., Oakes, L., O'Brien, P., Ocampo, C., Occhipinti, G., Ochoa, J. P., de Bhroithe, A. OFaolain, Oger, R., Ohira, Y., Ohishi, M., Ohm, S., Ohoka, H., Okazaki, N., Okumura, A., Olive, J. -F., Olszowski, D., Ong, R. A., Ono, S., Orienti, M., Orito, R., Orlati, A., Osborne, J., Ostrowski, M., Ottaway, D., Otte, N., Öttl, S., Ovcharov, E., Oya, I., Ozieblo, A., Padovani, M., Pagano, I., Paiano, S., Paizis, A., Palacio, J., Palatka, M., Pallotta, J., Panagiotidis, K., Panazol, J. -L., Paneque, D., Panter, M., Panzera, M. R., Paoletti, R., Paolillo, M., Papayannis, A., Papyan, G., Paravac, A., Paredes, J. M., Pareschi, G., Park, N., Parsons, D., Paśko, P., Pavy, S., Pech, M., Peck, A., Pedaletti, G., Pe'er, A., Peet, S., Pelat, D., Pepato, A., Perez, M. d. C., Perri, L., Perri, M., Persic, M., Petrashyk, A., Petrucci, P. -O., Petruk, O., Peyaud, B., Pfeifer, M., Pfeiffer, G., Piano, G., Pieloth, D., Pierre, E., de Pinho, F. Pinto, García, C. Pio, Piret, Y., Pisarski, A., Pita, S., Platos, Ł., Platzer, R., Podkladkin, S., Pogosyan, L., Pohl, M., Poinsignon, P., Pollo, A., Porcelli, A., Porthault, J., Potter, W., Poulios, S., Poutanen, J., Prandini, E., Prast, J., Pressard, K., Principe, G., Profeti, F., Prokhorov, D., Prokoph, H., Prouza, M., Pruchniewicz, R., Pruteanu, G., Pueschel, E., Pühlhofer, G., Puljak, I., Punch, M., Pürckhauer, S., Pyzioł, R., Queiroz, F., Quel, E. J., Quinn, J., Quirrenbach, A., Rafighi, I., Rainò, S., Rajda, P. J., Rameez, M., Rando, R., Rannot, R. C., Rataj, M., Ravel, T., Razzaque, S., Reardon, P., Reichardt, I., Reimann, O., Reimer, A., Reimer, O., Reisenegger, A., Renaud, M., Renner, S., Reposeur, T., Reville, B., Rezaeian, A., Rhode, W., Ribeiro, D., Prado, R. Ribeiro, Ribó, M., Richards, G., Richer, M. G., Richtler, T., Rico, J., Ridky, J., Rieger, F., Riquelme, M., Ristori, P. R., Rivoire, S., Rizi, V., Roache, E., Rodriguez, J., Fernandez, G. Rodriguez, Vázquez, J. J. Rodríguez, Rojas, G., Romano, P., Romeo, G., Roncadelli, M., Rosado, J., Rose, J., Rosen, S., Lees, S. Rosier, Ross, D., Rouaix, G., Rousselle, J., Rovero, A. C., Rowell, G., Roy, F., Royer, S., Rubini, A., Rudak, B., Rugliancich, A., Rujopakarn, W., Rulten, C., Rupiński, M., Russo, F., Rutkowski, K., Saavedra, O., Sabatini, S., Sacco, B., Sadeh, I., Saemann, E. O., Safi-Harb, S., Saggion, A., Sahakian, V., Saito, T., Sakaki, N., Sakurai, S., Salamon, A., Salega, M., Salek, D., Greus, F. Salesa, Salgado, J., Salina, G., Salinas, L., Salini, A., Sanchez, D., Sanchez-Conde, M., Sandaker, H., Sandoval, A., Sangiorgi, P., Sanguillon, M., Sano, H., Santander, M., Santangelo, A., Santos, E. M., Santos-Lima, R., Sanuy, A., Sapozhnikov, L., Sarkar, S., Satalecka, K., Sato, Y., Savalle, R., Sawada, M., Sayède, F., Schanne, S., Schanz, T., Schioppa, E. J., Schlenstedt, S., Schmid, J., Schmidt, T., Schmoll, J., Schneider, M., Schoorlemmer, H., Schovanek, P., Schubert, A., Schullian, E. -M., Schultze, J., Schulz, A., Schulz, S., Schure, K., Schussler, F., Schwab, T., Schwanke, U., Schwarz, J., Schweizer, T., Schwemmer, S., Schwendicke, U., Schwerdt, C., Sciacca, E., Scuderi, S., Segreto, A., Seiradakis, J. -H., Sembroski, G. H., Semikoz, D., Sergijenko, O., Serre, N., Servillat, M., Seweryn, K., Shafi, N., Shalchi, A., Sharma, M., Shayduk, M., Shellard, R. C., Shibata, T., Shigenaka, A., Shilon, I., Shum, E., Sidoli, L., Sidz, M., Sieiro, J., Siejkowski, H., Silk, J., Sillanpää, A., Simone, D., Simpson, H., Singh, B. B., Sinha, A., Sironi, G., Sitarek, J., Sizun, P., Sliusar, V., Smith, A., Sobczyńska, D., Sol, H., Sottile, G., Sowiński, M., Spanier, F., Spengler, G., Spiga, R., Stadler, R., Stahl, O., Stamerra, A., Stanič, S., Starling, R., Staszak, D., Stawarz, Ł., Steenkamp, R., Stefanik, S., Stegmann, C., Steiner, S., Stella, C., Stephan, M., Stergioulas, N., Sternberger, R., Sterzel, M., Stevenson, B., Stinzing, F., Stodulska, M., Stodulski, M., Stolarczyk, T., Stratta, G., Straumann, U., Stringhetti, L., Strzys, M., Stuik, R., Sulanke, K. -H., Suomijärvi, T., Supanitsky, A. D., Suric, T., Sushch, I., Sutcliffe, P., Sykes, J., Szanecki, M., Szepieniec, T., Szwarnog, P., Tacchini, A., Tachihara, K., Tagliaferri, G., Tajima, H., Takahashi, H., Takahashi, K., Takahashi, M., Takalo, L., Takami, S., Takata, J., Takeda, J., Talbot, G., Tam, T., Tanaka, M., Tanaka, S., Tanaka, T., Tanaka, Y., Tanci, C., Tanigawa, S., Tavani, M., Tavecchio, F., Tavernet, J. -P., Tayabaly, K., Taylor, A., Tejedor, L. A., Telezhinsky, I., Temme, F., Temnikov, P., Tenzer, C., Terada, Y., Terrazas, J. C., Terrier, R., Terront, D., Terzic, T., Tescaro, D., Teshima, M., Testa, V., Tezier, D., Thayer, J., Thornhill, J., Thoudam, S., Thuermann, D., Tibaldo, L., Tiengo, A., Timpanaro, M. C., Tiziani, D., Tluczykont, M., Peixoto, C. J. Todero, Tokanai, F., Tokarz, M., Toma, K., Tomastik, J., Tomono, Y., Tonachini, A., Tonev, D., Torii, K., Tornikoski, M., Torres, D. F., Torres, M., Torresi, E., Toso, G., Tosti, G., Totani, T., Tothill, N., Toussenel, F., Tovmassian, G., Toyama, T., Travnicek, P., Trichard, C., Trifoglio, M., Pujadas, I. Troyano, Trzeciak, M., Tsinganos, K., Tsujimoto, S., Tsuru, T., Uchiyama, Y., Umana, G., Umetsu, Y., Upadhya, S. S., Uslenghi, M., Vagelli, V., Vagnetti, F., Valdes-Galicia, J., Valentino, M., Vallania, P., Valore, L., van Driel, W., van Eldik, C., van Soelen, B., Vandenbroucke, J., Vanderwalt, J., Vasileiadis, G., Vassiliev, V., Vázquez, J. R., Acosta, M. L. Vázquez, Vecchi, M., Vega, A., Vegas, I., Veitch, P., Venault, P., Venema, L., Venter, C., Vercellone, S., Vergani, S., Verma, K., Verzi, V., Vettolani, G. P., Veyssiere, C., Viana, A., Viaux, N., Vicha, J., Vigorito, C., Vincent, P., Vincent, S., Vink, J., Vittorini, V., Vlahakis, N., Vlahos, L., Voelk, H., Voisin, V., Vollhardt, A., Volpicelli, A., von Brand, H., Vorobiov, S., Vovk, I., Vrastil, M., Vu, L. V., Vuillaume, T., Wagner, R., Wagner, S. J., Wakely, S. P., Walstra, T., Walter, R., Walther, T., Ward, J. E., Ward, M., Warda, K., Warren, D., Wassberg, S., Watson, J. J., Wawer, P., Wawrzaszek, R., Webb, N., Wegner, P., Weiner, O., Weinstein, A., Wells, R., Werner, F., Wetteskind, H., White, M., White, R., Więcek, M., Wierzcholska, A., Wiesand, S., Wijers, R., Wilcox, P., Wild, N., Wilhelm, A., Wilkinson, M., Will, M., Williams, D. A., Williams, J. T., Willingale, R., Wilson, N., Winde, M., Winiarski, K., Winkler, H., Winter, M., Wischnewski, R., Witt, E., Wojcik, P., Wolf, D., Wood, M., Wörnlein, A., Wu, E., Wu, T., Yadav, K. K., Yamamoto, H., Yamamoto, T., Yamane, N., Yamazaki, R., Yanagita, S., Yang, L., Yelos, D., Yoshida, A., Yoshida, M., Yoshida, T., Yoshiike, S., Yoshikoshi, T., Yu, P., Zabalza, V., Zaborov, D., Zacharias, M., Zaharijas, G., Zajczyk, A., Zampieri, L., Zandanel, F., Sanchez, R. Zanmar, Zaric, D., Zavrtanik, D., Zavrtanik, M., Zdziarski, A., Zech, A., Zechlin, H., Zhao, A., Zhdanov, V., Ziegler, A., Ziemann, J., Ziętara, K., Zink, A., Ziółkowski, J., Zitelli, V., Zoli, A., Zorn, J., and Żychowski, P.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
List of contributions from the Cherenkov Telescope Array (CTA) Consortium presented at the 6th International Symposium on High-Energy Gamma-Ray Astronomy (Gamma 2016), July 11-15, 2016, in Heidelberg, Germany., Comment: Index of CTA conference proceedings for the Gamma 2016, Heidelberg, Germany
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9. Very High Energy outburst of Markarian 501 in May 2009
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Aliu, E., Archambault, S., Archer, A., Arlen, T., Aune, T., Barnacka, A., Behera, B., Beilicke, M., Benbow, W., Berger, K., Bird, R., Bouvier, A., Böttcher, M., Buchovecky, M., Buckley, J. H., Bugaev, V., Cardenzana, J. V, Cerruti, M., Cesarini, A., 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., Gall, D., Gillanders, G. H., Griffin, S., Griffiths, S. T., Grube, J., Gyuk, G., Hütten, M., Håkansson, N., 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., de Bhróithe, A. O'Faoláin, Ong, R. A., Orr, M., Otte, A. N., Pandel, D., Park, N., Pelassa, V., Perkins, J. S., Pichel, A., Pohl, M., 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, I., 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, A., Williams, D. A., Zitzer, B., Baring, M. G., Gónzalez, J. Becerra, Cillis, A. N., Horan, D., and Paneque, D.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
The very high energy (VHE; E $>$ 100 GeV) blazar Markarian 501 was observed between April 17 and May 5 (MJD 54938--54956), 2009, as part of an extensive multi-wavelength campaign from radio to VHE. Strong VHE $\gamma$-ray activity was detected on May 1st with Whipple and VERITAS, when the flux (E $>$ 400 GeV) increased to 10 times the pre-flare baseline flux ($3.9{\times 10^{-11}}~{\rm ph~cm^{-2}~s^{-1}}$), 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$^{\circ}$. This VHE flare showed a fast flux variation with an increase of a factor $\sim$4 in 25 minutes, and a falling time of $\sim$50 minutes. 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., Comment: 13 pages, 10 figures. Accepted for publication in Astronomy and Astrophysics
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- 2016
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10. Stability, and electronic and optical properties of ternary nitride phases of MgSnN2: A first-principles study
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Dumre, B.B., Gall, D., and Khare, S.V.
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- 2021
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11. CTA Contributions to the 34th International Cosmic Ray Conference (ICRC2015)
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Consortium, The CTA, Abchiche, A., Abeysekara, U., Abril, Ó., Acero, F., Acharya, B. S., Actis, M., Agnetta, G., Aguilar, J. A., Aharonian, F., Akhperjanian, A., Albert, A., Alcubierre, M., Alfaro, R., Aliu, E., Allafort, A. J., Allan, D., Allekotte, I., Aloisio, R., Amans, J. -P., Amato, E., Ambrogi, L., Ambrosi, G., Ambrosio, M., Anderson, J., Anduze, M., Angüner, E. O., Antolini, E., Antonelli, L. A., Antonucci, M., Antonuccio, V., Antoranz, P., Aramo, C., Aravantinos, A., Argan, A., Armstrong, T., Arnaldi, H., Arnold, L., Arrabito, L., Arrieta, M., Asano, K., Asorey, H. G., Aune, T., Singh, C. B., Babic, A., Backes, M., Bais, A., Bajtlik, S., Balazs, C., Balbo, M., Balis, D., Balkowski, C., Ballester, O., Ballet, J., Balzer, A., Bamba, A., Bandiera, R., Barber, A., Barbier, C., Barceló, M., Barnacka, A., de Almeida, U. Barres, Barrio, J. A., Basso, S., Bastieri, D., Bauer, C., Baushev, A., Becciani, U., Becherini, Y., Tjus, J. Becker, Beckmann, V., Bednarek, W., Benbow, W., Ventura, D. Benedico, Berdugo, J., Berge, D., Bernardini, E., Bernhard, S., Bernlöhr, K., Bertucci, B., Besel, M. -A., Bhatt, N., Bhattacharjee, P., Bhattachryya, S., Biasuzzi, B., Bicknell, G., Bigongiari, C., Biland, A., Billotta, S., Bilnik, W., Biondo, B., Bird, T., Birsin, E., Bissaldi, E., Biteau, J., Bitossi, M., Bigas, O. Blanch, Blasi, P., Boehm, C., Bogacz, L., Bogdan, M., Bohacova, M., Boisson, C., Gargallo, J. Boix, Bolmont, J., Bonanno, G., Bonardi, A., Bonifacio, P., Bonnoli, G., Borkowski, J., Bose, R., Bosnjak, Z., Bottani, A., Böttcher, M., Bousquet, J. -J., Boutonnet, C., Bouyjou, F., Braiding, C., Brandt, L., Brau-Nogué, S., Bregeon, J., Bretz, T., Briggs, M., Brigida, M., Bringmann, T., Brisken, W., Brocato, E., Brook, P., Brown, A. M., Brun, P., Brunetti, G., Brunetti, L., Bruno, P., Bryan, M., Buanes, T., Bucciantini, N., Buchholtz, G., Buckley, J., Bugaev, V., Bühler, R., Bulgarelli, A., Bulik, T., Burton, M., Burtovoi, A., Busetto, G., Buson, S., Buss, J., Byrum, K., Cameron, R., Camprecios, J., Canelli, F., Canestrari, R., Cantu, S., Capalbi, M., Capasso, M., Capobianco, G., Caraveo, P., Cardenzana, J., Carius, S., Carlile, C., Carmona, E., Carosi, A., Carosi, R., Carr, J., Carroll, M., Carter, J., Carton, P. -H., Caruso, R., Casandjian, J. -M., Casanova, S., Cascone, E., Casiraghi, M., Castellina, A., Catalano, O., Catalanotti, S., Cavazzani, S., Cazaux, S., Cefalà, M., Cerchiara, P., Cereda, M., Cerruti, M., Chabanne, E., Chadwick, P., Champion, C., Chaty, S., Chaves, R., Cheimets, P., Chen, A., Chen, X., Chernyakova, M., Chiappetti, L., Chikawa, M., Chinn, D., Chitnis, V. R., Cho, N., Christov, A., Chudoba, J., Cieślar, M., Cillis, A., Ciocci, M. A., Clay, R., Cohen-Tanugi, J., Colafrancesco, S., Colin, P., Colombo, E., Colome, J., Colonges, S., Compin, M., Conforti, V., Connaughton, V., Connell, S., Conrad, J., Contreras, J. L., Coppi, P., Corbel, S., Coridian, J., Corona, P., Corti, D., Cortina, J., Cossio, L., Costa, A., Costantini, H., Cotter, G., Courty, B., Covino, S., Covone, G., Crimi, G., Criswell, S. J., Crocker, R., Croston, J., Cusumano, G., Da Vela, P., Dale, Ø., D'Ammando, F., Dang, D., Daniel, M., Davids, I., Dawson, B., Dazzi, F., Costa, B. de Aguiar, De Angelis, A., Cardoso, R. F. de Araujo, De Caprio, V., De Cesare, G., De Franco, A., De Frondat, F., Pino, E. M. de Gouveia Dal, de la Calle, I., De La Vega, G. A., Lopez, R. de los Reyes, De Lotto, B., De Luca, A., Neto, J. R. T. de Mello, de Naurois, M., Wilhelmi, E. de Oña, De Palma, F., de Souza, V., Decock, G., Deil, C., Del Santo, M., Delagnes, E., Deleglise, G., Delgado, C., della Volpe, D., Deloye, P., Depaola, G., Detournay, M., Dettlaff, A., Di Girolamo, T., Di Giulio, C., Di Paola, A., Di Pierro, F., Di Sciascio, G., Díaz, C., Dick, J., Dickinson, H., Diebold, S., Diez, V., Digel, S., Dipold, J., Disset, G., Distefano, A., Djannati-Ataï, A., Doert, M., Dohmke, M., Domainko, W., Dominik, N., Prester, D. Dominis, Donat, A., Donnarumma, I., Dorner, D., Doro, M., Dournaux, J. -L., Doyle, K., Drake, G., Dravins, D., Drury, L., Dubus, G., Dumas, D., Dumm, J., Durand, D., D'Urso, D., Dwarkadas, V., Dyks, J., Dyrda, M., Ebr, J., Echaniz, J. C., Edy, E., Egberts, K., Eger, P., Einecke, S., Eisch, J., Eisenkolb, F., Eleftheriadis, C., Elsässer, D., Emmanoulopoulos, D., Engelbrecht, C., Engelhaupt, D., Ernenwein, J. -P., Errando, M., Eschbach, S., Etchegoyen, A., Evans, P., Fairbairn, M., Falcone, A., Fantinel, D., Farakos, K., Farnier, C., Farrell, E., Farrell, S., Fasola, G., Fegan, S., Feinstein, F., Ferenc, D., Fernandez, A., Fernandez-Alonso, M., Ferreira, O., Fesquet, M., Fetfatzis, P., Fiasson, A., Filipčič, A., Filipovic, M., Fink, D., Finley, C., Finley, J. P., Finoguenov, A., Fioretti, V., Fiorini, M., Curcoll, R. Firpo, Fleischhack, H., Flores, H., Florin, D., Föhr, C., Fokitis, E., Font, L., Fontaine, G., Fontes, B., Forest, F., Fornasa, M., Förster, A., Fortin, P., Fortson, L., Fouque, N., Franckowiak, A., Franco, F. J., Frankowski, A., Frega, N., Albuquerque, I. Freire Mota, Coromina, L. Freixas, Fresnillo, L., Fruck, C., Fuessling, M., Fugazza, D., Fujita, Y., Fukami, S., Fukazawa, Y., Fukuda, T., Fukui, Y., Funk, S., Gäbele, W., Gabici, S., Gadola, A., Galante, N., Gall, D. D., Gallant, Y., Galloway, D., Gallozzi, S., Gao, S., Garcia, B., Gil, R. García, López, R. Garcia, Garczarczyk, M., Gardiol, D., Gargano, C., Gargano, F., Garozzo, S., Garrecht, F., Garrido, D., Garrido, L., Gascon, D., Gaskins, J., Gaudemard, J., Gaug, M., Gaweda, J., Geffroy, N., Gérard, L., Ghalumyan, A., Ghedina, A., Ghigo, M., Ghislain, P., Giannakaki, E., Gianotti, F., Giarrusso, S., Giavitto, G., Giebels, B., Giglietto, N., Gika, V., Gimenes, R., Giomi, M., Giommi, P., Giordano, F., Giovannini, G., Giro, E., Giroletti, M., Giuliani, A., Glicenstein, J. -F., Godinovic, N., Goldoni, P., Berisso, M. Gomez, Vargas, G. A. Gomez, Gonzalez, M. M., González, A., González, F., Muñoz, A. González, Gothe, K. S., Gotz, D., Grabarczyk, T., Graciani, R., Grandi, P., Grañena, F., Granot, J., Grasseau, G., Gredig, R., Green, A. J., Green, A. M., Greenshaw, T., Grenier, I., Grillo, A., Grondin, M. -H., Grube, J., Grudzinska, M., Grygorczuk, J., Guarino, V., Guberman, D., Gunji, S., Gyuk, G., Hadasch, D., Hagedorn, A., Hahn, J., Hakansson, N., Heras, N. Hamer, Hanabata, Y., Hara, S., Hardcastle, M. J., Harris, J., Hassan, T., Hatanaka, K., Haubold, T., Haupt, A., Hayakawa, T., Hayashida, M., Heller, M., Heller, R., Henault, F., Henri, G., Hermann, G., Hermel, R., Llorente, J. Herrera, Herrero, A., Hervet, O., Hidaka, N., Hinton, J., Hirai, W., Hirotani, K., Hoard, D., Hoffmann, D., Hofmann, W., Hofverberg, P., Holch, T., Holder, J., Hooper, S., Horan, D., Hörandel, J. R., Hormigos, S., Horns, D., Hose, J., Houles, J., Hovatta, T., Hrabovsky, M., Hrupec, D., Huet, J. -M., Hütten, M., Humensky, T. B., Huovelin, J., Huppert, J. -F., Iacovacci, M., Ibarra, A., Idźkowski, B., Ikawa, D., Illa, J. M., Impiombato, D., Incorvaia, S., Inome, Y., Inoue, S., Inoue, T., Inoue, Y., Iocco, F., Ioka, K., Iori, M., Ishio, K., Israel, G. L., Jablonski, C., Jacholkowska, A., Jacquemier, J., Jamrozy, M., Janecek, P., Janiak, M., Jankowsky, F., Jean, P., Jeanney, C., Jegouzo, I., Jenke, P., Jimenez, J. J., Jingo, M., Jocou, L., Jogler, T., Johnson, C. A., Journet, L., Juffroy, C., Jung, I., Kaaret, P. E., Kagaya, M., Kakuwa, J., Kalekin, O., Kalkuhl, C., Kankanyan, R., Karastergiou, A., Kärcher, K., Karczewski, M., Karkar, S., Karn, P., Kasperek, J., Katagiri, H., Kataoka, J., Katarzyński, K., Katz, U., Kaufmann, S., Kawanaka, N., Kawashima, T., Kazanas, D., Kelley-Hoskins, N., Kellner-Leidel, B., Kendziorra, E., Kersten, J., Khélifi, B., Kieda, D. B., Kihm, T., Kisaka, S., Kissmann, R., Klepser, S., Kluźniak, W., Knapen, J., Knapp, J., Knödlseder, J., Köck, F., Kocot, J., Kodakkadan, A., Kodani, K., Kohri, K., Kojima, T., Kokkotas, K., Kolitzus, D., Komin, N., Kominis, I., Konno, Y., Kosack, K., Koss, G., Koul, R., Kowal, G., Koyama, S., Kozioł, J., Kraus, M., Krause, J., Krause, M., Krawzcynski, H., Krennrich, F., Kretzschmann, A., Kruger, P., Kubo, H., Kudryavtsev, V., Mezek, G. Kukec, Kushida, J., Kuznetsov, A., La Barbera, A., La Palombara, N., La Parola, V., La Rosa, G., Laffon, H., Lagadec, T., Lahmann, R., Lalik, K., Lamanna, G., Landriu, D., Landt, H., Lang, R. G., Languignon, D., Lapington, J., Laporte, P., Latovski, N., Law-Green, D., Fèvre, J. -P. Le, Flour, T. Le, Sidaner, P. Le, Lee, S. -H., Lee, W. H., Leffhalm, K., Leich, H., de Oliveira, M. A. Leigui, Lelas, D., Lemière, A., Lemoine-Goumard, M., Lenain, J. -P., Leonard, R., Leoni, R., Lessio, L., Leto, G., Leveque, A., Lieunard, B., Limon, M., Lindemann, R., Lindfors, E., Liolios, A., Lipniacka, A., Lockart, H., Lohse, T., Loiseau, D., Łokas, E., Lombardi, S., Longo, F., Longo, G., Lopatin, A., Lopez, M., López-Coto, R., López-Oramas, A., Loreggia, D., Louge, T., Louis, F., Lu, C. -C., Lucarelli, F., Lucchesi, D., Lüdecke, H., Luque-Escamilla, P. L., Luz, O., Lyard, E., Maccarone, M. C., Maccarone, T. J., Mach, E., Madejski, G. M., Madonna, A., Mahabir, M., Maier, G., Majumdar, P., Makariev, M., Malaguti, G., Malaspina, G., Mallot, A. K., Maltezos, S., Mancilla, A., Mandat, D., Maneva, G., Manigot, P., Mankushiyil, N., Mannheim, K., Maragos, N., Marano, D., Marchegiani, P., Marcomini, J. A., Marcowith, A., Mariotti, M., Marisaldi, M., Markoff, S., Marszałek, A., Martens, C., Martí, J., Martin, J. -M., Martin, P., Martínez, G., Martínez, M., Martínez, O., Marx, R., Massimino, P., Mastichiadis, A., Mastroianni, S., Mastropietro, M., Masuda, S., Matsumoto, H., Matsuoka, S., Mattiazzo, S., Maurin, G., Maxted, N., Maya, J., Mayer, M., Mazin, D., Mazureau, E., Mazziotta, M. N., Comb, L. Mc, McCann, A., McCubbin, N., McHardy, I., McKay, R., McKinney, K., Meagher, K., Medina, C., Mehrez, F., Melioli, C., Melkumyan, D., Melo, D., Melse, T., Mereghetti, S., Mertsch, P., Meyer, M., Meyrelles jr, J. L., Miccichè, A., Michałowski, J., Micolon, P., Mientjes, P., Mignot, S., Mihailidis, A., Mineo, T., Minuti, M., Mirabal, N., Mirabel, F., Miranda, J. M., Mirzoyan, R., Mistò, A., Mitchell, A., Mizuno, T., Moderski, R., Mognet, I., Mohammed, M., Moharana, R., Molinari, E., Monmarthe, E., Monnier, G., Montaruli, T., Monte, C., Monteiro, I., Moore, P., Olaizola, A. Moralejo, Morello, C., Moretti, E., Mori, K., Morlino, G., Morselli, A., Mottez, F., Moudden, Y., Moulin, E., Mrusek, I., Mueller, S., Mukherjee, R., Munar-Adrover, P., Mundell, C., Muraishi, H., Murase, K., Muronga, A., Murphy, A., Nagataki, S., Nagayoshi, T., Nagesh, B. K., Naito, T., Nakajima, D., Nakamori, T., Nakayama, K., Naumann, D., Nayman, P., Nellen, L., Nemmen, R., Neronov, A., Neustroev, V., Neyroud, N., Nguyen, T., Nicastro, L., Nicolau-Kukliński, J., Niederwanger, F., Niedźwiecki, A., Niemiec, J., Nieto, D., Nievas, M., Nikolaidis, A., Nishijima, K., Nishikawa, K. -I., Noda, K., Nogues, L., Nolan, S., Northrop, R., Nosek, D., Nozka, L., Nunio, F., Oakes, L., O'Brien, P., Occhipinti, G., de Bhroithe, A. O'Faolain, Ogino, M., Ohira, Y., Ohishi, M., Ohm, S., Ohoka, H., Okumura, A., Olive, J. -F., Olszowski, D., Ong, R. A., Ono, S., Orienti, M., Orito, R., Orlati, A., Osborne, J., Ostrowski, M., Otero, L. A., Ottaway, D., Otte, N., Oya, I., Ozieblo, A., Padovani, M., Pagano, I., Paiano, S., Paizis, A., Palacio, J., Palatka, M., Pallotta, J., Panagiotidis, K., Panazol, J. -L., Paneque, D., Panter, M., Panzera, M. R., Paoletti, R., Paolillo, M., Papayannis, A., Papyan, G., Paravac, A., Paredes, J. M., Pareschi, G., Park, N., Parsons, D., Paśko, P., Pavy, S., Arribas, M. Paz, Pech, M., Peck, A., Pedaletti, G., Peet, S., Pelassa, V., Pelat, D., Peres, C., Perez, M. d. C., Perri, L., Persic, M., Petrashyk, A., Petrucci, P. -O., Peyaud, B., Pfeifer, M., Pfeiffer, G., Piano, G., Pichel, A., Pieloth, D., Pierbattista, M., Pierre, E., de Pinho, F. Pinto, García, C. Pio, Piret, Y., Pita, S., Planes, A., Platino, M., Platos, Ł., Platzer, R., Podkladkin, S., Pogosyan, L., Pohl, M., Poinsignon, P., Ponz, J. D., Porcelli, A., Potter, W., Poulios, S., Poutanen, J., Prandini, E., Prast, J., Preece, R., Profeti, F., Prokhorov, D., Prokoph, H., Prouza, M., Proyetti, M., Pruchniewicz, R., Pueschel, E., Pühlhofer, G., Puljak, I., Punch, M., Pyzioł, R., Queiroz, F., Quel, E. J., Quinn, J., Quirrenbach, A., Racero, E., Räck, T., Rafalski, J., Rafighi, I., Rainò, S., Rajda, P. J., Rameez, M., Rando, R., Rannot, R. C., Rataj, M., Rateau, S., Ravel, T., Ravignani, D., Razzaque, S., Reardon, P., Reimann, O., Reimer, A., Reimer, O., Reitberger, K., Renaud, M., Renner, S., Reposeur, T., Rettig, R., Reville, B., Rhode, W., Ribeiro, D., Ribó, M., Richards, G., Richer, M. G., Rico, J., Ridky, J., Rieger, F., Ringegni, P., Ristori, P. R., Rivière, A., Rivoire, S., Roache, E., Rodeghiero, G., Rodriguez, J., Fernandez, G. Rodriguez, Vázquez, J. J. Rodríguez, Rogers, T., Rojas, G., Romano, P., Rodriguez, M. P. Romay, Romeo, G., Romero, G. E., Roncadelli, M., Rose, J., Rosen, S., Lees, S. Rosier, Ross, D., Rossiter, P., Rouaix, G., Rousselle, J., Rovero, A. C., Rowell, G., Roy, F., Royer, S., Różańska, A., Rudak, B., Rugliancich, A., Rulten, C., Rupiński, M., Russo, F., Rutkowski, K., Saavedra, O., Sabatini, S., Sacco, B., Saemann, E. O., Saggion, A., Saha, L., Sahakian, V., Saito, K., Saito, T., Sakaki, N., Salega, M., Salek, D., Salgado, J., Salini, A., Sanchez, D., Sanchez, F., Sanchez-Conde, M., Sandaker, H., Sandoval, A., Sangiorgi, P., Sanguillon, M., Sano, H., Santander, M., Santangelo, A., Santos, E. M., Santos-Lima, R., Sanuy, A., Sapozhnikov, L., Sarkar, S., Satalecka, K., Savalle, R., Sawada, M., Sayède, F., Schafer, J., Schanne, S., Schanz, T., Schioppa, E. J., Schlenstedt, S., Schlickeiser, R., Schmidt, T., Schmoll, J., Schneider, M., Schovanek, P., Schubert, A., Schultz, C., Schultze, J., Schulz, A., Schulz, S., Schure, K., Schussler, F., Schwab, T., Schwanke, U., Schwarz, J., Schweizer, T., Schwemmer, S., Schwendicke, U., Schwerdt, C., Segreto, A., Seiradakis, J. -H., Sembroski, G. H., Semikoz, D., Serre, N., Servillat, M., Seweryn, K., Shafi, N., Sharma, M., Shayduk, M., Shellard, R. C., Shibata, T., Pandeni, K. Shiningayamwe, Shukla, A., Shum, E., Sidoli, L., Sidz, M., Sieiro, J., Siejkowski, H., Silk, J., Sillanpää, A., Simone, D., Singh, B. B., Sinha, A., Sironi, G., Sitarek, J., Sizun, P., Slyusar, V., Smith, A., Smith, J., Sobczyńska, D., Sol, H., Sottile, G., Sowiński, M., Spanier, F., Spengler, G., Spiga, D., Stadler, R., Stahl, O., Stamatescu, V., Stamerra, A., Stanič, S., Starling, R., Stawarz, Ł., Steenkamp, R., Stefanik, S., Stegmann, C., Steiner, S., Stella, C., Stergioulas, N., Sternberger, R., Sterzel, M., Stevenson, B., Stinzing, F., Stodulska, M., Stodulski, M., Stolarczyk, T., Straumann, U., Strazzeri, E., Stringhetti, L., Strzys, M., Stuik, R., Sulanke, K. -H., Supanitsky, A. D., Suric, T., Sushch, I., Sutcliffe, P., Sykes, J., Szanecki, M., Szepieniec, T., Szwarnog, P., Tacchini, A., Tachihara, K., Tagliaferri, G., Tajima, H., Takahashi, H., Takahashi, K., Takahashi, M., Takalo, L., Takami, H., Talbot, G., Tammi, J., Tanaka, M., Tanaka, S., Tanaka, T., Tanaka, Y., Tanci, C., Tarantino, E., Tavani, M., Tavecchio, F., Tavernet, J. -P., Tayabaly, K., Tejedor, L. A., Telezhinsky, I., Temme, F., Temnikov, P., Tenzer, C., Terada, Y., Terrier, R., Tescaro, D., Teshima, M., Testa, V., Tezier, D., Thayer, J., Thomas, V., Thornhill, J., Thuermann, D., Tibaldo, L., Tibolla, O., Tiengo, A., Tijsseling, G., Timpanaro, M. C., Tluczykont, M., Peixoto, C. J. Todero, Tokanai, F., Tokarz, M., Toma, K., Tomastik, J., Tomono, Y., Tonachini, A., Tonev, D., Torii, K., Tornikoski, M., Torres, D. F., Torres, M., Torresi, E., Toscano, S., Toso, G., Tosti, G., Totani, T., Tothill, N., Toussenel, F., Tovmassian, G., Townsley, C., Toyama, T., Travnicek, P., Trifoglio, M., Pujadas, I. Troyano, Trzeciak, M., Tsinganos, K., Tsubone, Y., Tsuchiya, Y., Tsujimoto, S., Tsuru, T., Uchiyama, Y., Umana, G., Umetsu, Y., Underwood, C., Upadhya, S. S., Uslenghi, M., Vagnetti, F., Valdes-Galicia, J., Vallania, P., Vallejo, G., Valore, L., van Driel, W., van Eldik, C., van Soelen, B., Vandenbroucke, J., Vanderwalt, J., Vasileiadis, G., Vassiliev, V., Acosta, M. L. Vázquez, Vecchi, M., Vegas, I., Veitch, P., Venema, L., Venter, C., Vercellone, S., Vergani, S., Verma, K., Verzi, V., Vettolani, G. P., Viana, A., Vicha, J., Videla, M., Vigorito, C., Vincent, P., Vincent, S., Vink, J., Vittorini, V., Vlahakis, N., Vlahos, L., Voelk, H., Vogler, P., Voisin, V., Vollhardt, A., Volpicelli, A., Vorobiov, S., Vovk, I., Vu, L. V., Wagner, R., Wagner, R. M., Wagner, R. G., Wagner, S. J., Wakely, S. P., Walter, R., Walther, T., Ward, J. E., Ward, M., Warda, K., Warwick, R., Wassberg, S., Watson, J., Wawer, P., Wawrzaszek, R., Webb, N., Wegner, P., Weinstein, A., Weitzel, Q., Wells, R., Werner, F., Werner, M., Wetteskind, H., White, M., White, R., Więcek, M., Wierzcholska, A., Wiesand, S., Wijers, R., Wild, N., Wilhelm, A., Wilkinson, M., Will, M., Williams, D. A., Williams, J. T., Willingale, R., Winde, M., Winiarski, K., Winkler, H., Wischnewski, R., Wojcik, P., Wolf, D., Wood, M., Wörnlein, A., Wu, E., Wu, T., Yadav, K. K., Yamamoto, H., Yamamoto, T., Yamazaki, R., Yanagita, S., Yang, L., Yebras, J. M., Yelos, D., Yeung, W., Yoshida, A., Yoshida, T., Yoshiike, S., Yoshikoshi, T., Yu, P., Zabalza, V., Zacharias, M., Zaharijas, G., Zajczyk, A., Zampieri, L., Zandanel, F., Zanin, R., Sanchez, R. Zanmar, Zavrtanik, D., Zavrtanik, M., Zdziarski, A., Zech, A., Zechlin, H., Zhao, A., Ziegler, A., Ziemann, J., Ziętara, K., Ziółkowski, J., Zitelli, V., Zoli, A., Zurbach, C., and Żychowski, P.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
List of contributions from the CTA Consortium presented at the 34th International Cosmic Ray Conference, 30 July - 6 August 2015, The Hague, The Netherlands., Comment: Index of CTA conference proceedings at the ICRC2015, The Hague (The Netherlands). v1: placeholder with no arXiv links yet, to be replaced once individual contributions have been all submitted; v2: final with arXiv links to all CTA contributions and full author list
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- 2015
12. Investigating the TeV Morphology of MGRO J1908+06 with VERITAS
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Aliu, E., Archambault, S., Aune, T., Behera, B., Beilicke, M., Benbow, W., Berger, K., Bird, R., Buckley, J. H., Bugaev, V., Cardenzana, J. V, Cerruti, M., Chen, X., Ciupik, L., Collins-Hughes, E., Connolly, M. P., Cui, W., Dumm, J., Dwarkadas, V. V., Errando, M., Falcone, A., Federici, S., 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., Hanna, D., Holder, J., Hughes, G., Humensky, T. B., Kaaret, P., Kertzman, M., Khassen, Y., Kieda, D., Krennrich, F., Kumar, S., Lang, M. J., Madhavan, A. S, Maier, G., McCann, A. J., Meagher, K., Millis, J., Moriarty, P., Mukherjee, R., Nieto, D., de Bhroithe, A. O'Faolain, Ong, R. A., Otte, A. N., Pandel, D., Park, N., Pohl, M., Popkow, A., Prokoph, H., Quinn, J., Ragan, K., Rajotte, J., Ratliff, G., Reyes, L. C., Reynolds, P. T., Richards, G. T., Roache, E., Rousselle, J., Sembroski, G. H., Shahinyan, K., Sheidaei, F., Smith, A. W., Staszak, D., Telezhinsky, I., Tsurusaki, K., Tucci, J. V., Tyler, J., Varlotta, A., Vassiliev, V. V., Vincent, S., Wakely, S. P., Ward, J. E., Weinstein, A., Welsing, R., and Wilhelm, A.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We report on deep observations of the extended TeV gamma-ray source MGRO J1908+06 made with the VERITAS very high energy (VHE) gamma-ray observatory. Previously, the TeV emission has been attributed to the pulsar wind nebula (PWN) of the Fermi-LAT pulsar PSR J1907+0602. We detect MGRO J1908+06 at a significance level of 14 standard deviations (14 sigma) and measure a photon index of 2.20 +/- 0.10_stat +/- 0.20_sys. The TeV emission is extended, covering the region near PSR J1907+0602 and also extending towards SNR G40.5--0.5. When fitted with a 2-dimensional Gaussian, the intrinsic extension has a standard deviation of sigma_src = 0.44 +/- 0.02 degrees. In contrast to other TeV PWNe of similar age in which the TeV spectrum softens with distance from the pulsar, the TeV spectrum measured near the pulsar location is consistent with that measured at a position near the rim of G40.5--0.5, 0.33 degrees away., Comment: To appear in ApJ, 8 pages
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- 2014
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13. Observation of Markarian 421 in TeV gamma rays over a 14-year time span
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Acciari, V. A., Arlen, T., Aune, T., Benbow, W., Bird, R., Bouvier, A., Bradbury, S. M., Buckley, J. H., Bugaev, V., Perez, I. de la Calle, Carter-Lewis, D. A., Cesarini, A., Ciupik, L., Collins-Hughes, E., Connolly, M. P., Cui, W., Duke, C., Dumm, J., Falcone, A., Federici, S., Fegan, D. J., Fegan, S. J., Finley, J. P., Finnegan, G., Fortson, L., Gaidos, J., Galante, N., Gall, D., Gibbs, K., Gillanders, G. H., Griffin, S., Grube, J., Gyuk, G., Hanna, D., Horan, D., Humensky, T. B., Kaaret, P., Kertzman, M., Khassen, Y., Kieda, D., Krawczynski, H., Krennrich, F., Lang, M. J., McEnery, J. E., Madhavan, A. S., Moriarty, P., Nelson, T., de Bhróithe, A. O'Faoláin, Ong, R. A., Orr, M., Otte, A. N., Perkins, J. S., Petry, D., Pichel, A., Pohl, M., Quinn, J., Ragan, K., Reynolds, P. T., Roache, E., Rovero, A., Schroedter, M., Sembroski, G. H., Smith, A., Telezhinsky, I., Theiling, M., Toner, J., Tyler, J., Varlotta, A., Vivier, M., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Welsing, R., Williams, D. A., and Wissel, S.
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Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
The variability of the blazar Markarian 421 in TeV gamma rays over a 14-year time period has been explored with the Whipple 10 m telescope. It is shown that the dynamic range of its flux variations is large and similar to that in X-rays. A correlation between the X-ray and TeV energy bands is observed during some bright flares and when the complete data sets are binned on long timescales. The main database consists of 878.4 hours of observation with the Whipple telescope, spread over 783 nights. The peak energy response of the telescope was 400 GeV with 20% uncertainty. This is the largest database of any TeV-emitting active galactic nucleus (AGN) and hence was used to explore the variability profile of Markarian 421. The time-averaged flux from Markarian 421 over this period was 0.446$\pm$0.008 Crab flux units. The flux exceeded 10 Crab flux units on three separate occasions. For the 2000-2001 season the average flux reached 1.86 Crab units, while in the 1996-1997 season the average flux was only 0.23 Crab units., Comment: 29 pages, 15 figures. Accepted for publication in Astroparticle Physics
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- 2013
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14. Discovery of a new TeV gamma-ray source: VER J0521+211
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VERITAS Collaboration, Archambault, S., Arlen, T., Aune, T., Beilicke, M., Benbow, W., Bird, R., Bouvier, A., Buckley, J. H., Bugaev, V., Byrum, K., Cesarini, A., Ciupik, L., Connolly, M. P., Cui, W., Errando, M., Falcone, A., Federici, S., Feng, Q., Finley, J. P., Fortson, L., Furniss, A., Galante, N., Gall, D., Gillanders, G. H., Griffin, S., Grube, J., Gyuk, G., Hanna, D., Holder, J., Hughes, G., Humensky, T. B., Kaaret, P., Kertzman, M., Khassen, Y., Kieda, D., Krawczynski, H., Krennrich, F., Kumar, S., Lang, M. J., Madhavan, A. S, Maier, G., Majumdar, P., McArthur, S., McCann, A., Millis, J., Moriarty, P., Mukherjee, R., de Bhroithe, A. O'Faolain, Ong, R. A., Otte, A. N., Park, N., Perkins, J. S., Pohl, M., Popkow, A., Prokoph, H., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Richards, G. T., Roache, E., Saxon, D. B., Sembroski, G. H., Smith, A. W., Staszak, D., Telezhinsky, I., Theiling, M., Varlotta, A., Vassiliev, V. V., Vincent, S., Wakely, S. P., Weekes, T. C., Weinstein, A., Welsing, R., Williams, D. A., Zitzer, B., Bottcher, M., Fegan, S. J., Fortin, P., Halpern, J. P., Kovalev, Y. Y., Lister, M. L., Liu, J., Pushkarev, A. B., and Smith, P. S.
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Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Cosmology and Extragalactic Astrophysics - Abstract
We report the detection of a new TeV gamma-ray source, VER J0521+211, based on observations made with the VERITAS imaging atmospheric Cherenkov telescope array. These observations were motivated by the discovery of a cluster of >30GeV photons in the first year of Fermi-LAT observations. VER J0521+211 is relatively bright at TeV energies, with a mean photon flux of 1.93 +/- 0.13_stat +/- 0.78_sys 10^-11 cm-2 s-1 above 0.2 TeV during the period of the VERITAS observations. The source is strongly variable on a daily timescale across all wavebands, from optical to TeV, with a peak flux corresponding to ~0.3 times the steady Crab Nebula flux at TeV energies. Follow-up observations in the optical and X-ray bands classify the newly-discovered TeV source as a BL Lac-type blazar with uncertain redshift, although recent measurements suggest z=0.108. VER J0521+211 exhibits all the defining properties of blazars in radio, optical, X-ray, and gamma-ray wavelengths., Comment: 10 pages, 8 figures, 3 tables. Accepted by The Astrophysical Journal
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- 2013
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15. Multiwavelength observations and modeling of 1ES 1959+650 in a low flux state
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VERITAS Collaboration, Aliu, E., Archambault, S., Arlen, T., Aune, T., Beilicke, M., Benbow, W., Bird, R., Boettcher, M., Bouvier, A., Bugaev, V., Byrum, K., Cesarini, A., Ciupik, L., Collins-Hughes, E., Connolly, M. P., Cui, W., Dickherber, R., Duke, C., Dumm, J., Errando, M., Falcone, A., Federici, S., Feng, Q., Finley, J. P., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Gillanders, G. H., Griffin, S., Grube, J., Gyuk, G., Hanna, D., Holder, J., Hughes, G., Humensky, T. B., Kaaret, P., Kertzman, M., Khassen, Y., Kieda, D., Krawczynski, H., Krennrick, F., Lang, M. J., Madhavan, A. S., Maier, G., Majumdar, P., McArthur, S., McCann, A., Moriarty, P., Mukherjee, R., Nelson, T., de Bhroithe, A. O'Faolain, Ong, R. A., Orr, M., Otte, A. N., Park, N., Perkins, J. S., Pichel, A., Pohl, M., Popkow, A., Prokoph, H., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Saxon, D. B., Schroedter, M., Sembroski, G. H., Skole, C., Smith, A. W., Staszak, D., Telezhinsky, I., Theiling, M., Tyler, J., Varlotta, A., Vassiliev, V. V., Wakely, S. P., Weekes, T. C., Weinstein, A., Welsing, R., Williams, D. A., and Zitzer, B.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We report on the VERITAS observations of the high-frequency peaked BL Lac object 1ES 1959+650 in the period 2007-2011. This source is detected at TeV energies by VERITAS at 16.4 standard deviation (sigma) significance in 7.6 hours of observation in a low flux state. A multiwavelength spectral energy distribution (SED) is constructed from contemporaneous data from VERITAS, Fermi-LAT, RXTE PCA, and Swift UVOT. Swift XRT data is not included in the SED due to a lack of simultaneous observations with VERITAS. In contrast to the orphan gamma-ray flare exhibited by this source in 2002, the X-ray flux of the source is found to vary by an order of magnitude, while other energy regimes exhibit less variable emission. A quasi-equilibrium synchrotron self-Compton model with an additional external radiation field is used to describe three SEDs corresponding to the lowest, highest, and average X-ray states. The variation in the X-ray spectrum is modeled by changing the electron injection spectral index, with minor adjustments of the kinetic luminosity in electrons. This scenario produces small-scale flux variability of order >~2 in the HE (E>1 MeV) and VHE (E>100 GeV) gamma-ray regimes, which is corroborated by the Fermi-LAT, VERITAS, and Whipple 10m telescope light curves., Comment: 9 pages, 7 figures. This is an author-created, un-copyedited version of an article accepted for publication in The Astrophysical Journal. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it
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- 2013
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16. CTA contributions to the 33rd International Cosmic Ray Conference (ICRC2013)
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Consortium, The CTA, Abril, O., Acharya, B. S., Actis, M., Agnetta, G., Aguilar, J. A., Aharonian, F., Ajello, M., Akhperjanian, A., Alcubierre, M., Aleksic, J., Alfaro, R., Aliu, E., Allafort, A. J., Allan, D., Allekotte, I., Aloisio, R., Amato, E., Ambrosi, G., Ambrosio, M., Anderson, J., Angüner, E. O., Antonelli, L. A., Antonuccio, V., Antonucci, M., Antoranz, P., Aravantinos, A., Argan, A., Arlen, T., Aramo, C., Armstrong, T., Arnaldi, H., Arrabito, L., Asano, K., Ashton, T., Asorey, H. G., Aune, T., Awane, Y., Baba, H., Babic, A., Baby, N., Bähr, J., Bais, A., Baixeras, C., Bajtlik, S., Balbo, M., Balis, D., Balkowski, C., Ballet, J., Bamba, A., Bandiera, R., Barber, A., Barbier, C., Barceló, M., Barnacka, A., Barnstedt, J., de Almeida, U. Barres, Barrio, J. A., Basili, A., Basso, S., Bastieri, D., Bauer, C., Baushev, A., Becciani, U., Becerra, J., Becherini, Y., Bechtol, K. C., Tjus, J. Becker, Beckmann, V., Bednarek, W., Behera, B., Belluso, M., Benbow, W., Berdugo, J., Berge, D., Berger, K., Bernard, F., Bernardino, T., Bernlöhr, K., Bertucci, B., Bhat, N., Bhattacharyya, S., Biasuzzi, B., Bigongiari, C., Biland, A., Billotta, S., Bird, T., Birsin, E., Bissaldi, E., Biteau, J., Bitossi, M., Blake, S., Bigas, O. Blanch, Blasi, P., Bobkov, A., Boccone, V., Böttcher, M., Bogacz, L., Bogart, J., Bogdan, M., Boisson, C., Gargallo, J. Boix, Bolmont, J., Bonanno, G., Bonardi, A., Bonev, T., Bonifacio, P., Bonnoli, G., Bordas, P., Borgland, A., Borkowski, J., Bose, R., Botner, O., Bottani, A., Bouchet, L., Bourgeat, M., Boutonnet, C., Bouvier, A., Brau-Nogué, S., Braun, I., Bretz, T., Briggs, M., Brigida, M., Bringmann, T., Britto, R., Brook, P., Brun, P., Brunetti, L., Bruno, P., Bucciantini, N., Buanes, T., Buckley, J., Bühler, R., Bugaev, V., Bulgarelli, A., Bulik, T., Busetto, G., Buson, S., Byrum, K., Cailles, M., Cameron, R., Camprecios, J., Canestrari, R., Cantu, S., Capalbi, M., Caraveo, P., Carmona, E., Carosi, A., Carosi, R., Carr, J., Carter, J., Carton, P. -H., Caruso, R., Casanova, S., Cascone, E., Casiraghi, M., Castellina, A., Catalano, O., Cavazzani, S., Cazaux, S., Cerchiara, P., Cerruti, M., Chabanne, E., Chadwick, P., Champion, C., Chaves, R., Cheimets, P., Chen, A., Chiang, J., Chiappetti, L., Chikawa, M., Chitnis, V. 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Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Instrumentation and Methods for Astrophysics ,High Energy Physics - Experiment - Abstract
Compilation of CTA contributions to the proceedings of the 33rd International Cosmic Ray Conference (ICRC2013), which took place in 2-9 July, 2013, in Rio de Janeiro, Brazil, Comment: Index of CTA conference proceedings at the ICRC2013, Rio de Janeiro (Brazil). v1: placeholder with no arXiv links yet, to be replaced once individual contributions have been all submitted. v2: final with arXiv links to all CTA contributions and full author list
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17. Discovery of TeV Gamma-ray Emission Toward Supernova Remnant SNR G78.2+2.1
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Aliu, E., Archambault, S., Arlen, T., Aune, T., Beilicke, M., Benbow, W., Bird, R., Bouvier, A., Bradbury, S. M., Buckley, J. H., Bugaev, V., Byrum, K., Cannon, A., Cesarini, A., Ciupik, L., Collins-Hughes, E., Connolly, M. P., Cui, W., Dickherber, R., Duke, C., Dumm, J., Dwarkadas, V. V., Errando, M., Falcone, A., Federici, S., Feng, Q., Finley, J. P., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Gillanders, G. H., Godambe, S., Gotthelf, E. V., Griffin, S., Grube, J., Gyuk, G., Hanna, D., Holder, J., Huan, H., Hughes, G., Humensky, T. B., Kaaret, P., Karlsson, N., Kertzman, M., Khassen, Y., Kieda, D., Krawczynski, H., Krennrich, F., Lang, M. J., Lee, K., Madhavan, A. S, Maier, G., Majumdar, P., McArthur, S., McCann, A., Millis, J., Moriarty, P., Mukherjee, R., Nelson, T., de Bhróithe, A. O'Faoláin, Ong, R. A., Orr, M., Otte, A. N., Pandel, D., Park, N., Perkins, J. S., Pohl, M., Popkow, A., Prokoph, H., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Rose, H. J., Ruppel, J., Saxon, D. B., Schroedter, M., Sembroski, G. H., Şentürk, G. D., Skole, C., Telezhinsky, I., Tešić, G., Theiling, M., Thibadeau, S., Tsurusaki, K., Tyler, J., Varlotta, A., Vassiliev, V. V., Vincent, S., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Welsing, R., Williams, D. A., and Zitzer, B.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We report the discovery of an unidentified, extended source of very-high-energy (VHE) gamma-ray emission, VER J2019+407, within the radio shell of the supernova remnant SNR G78.2+2.1, using 21.4 hours of data taken by the VERITAS gamma-ray observatory in 2009. These data confirm the preliminary indications of gamma-ray emission previously seen in a two-year (2007-2009) blind survey of the Cygnus region by VERITAS. VER J2019+407, which is detected at a post-trials significance of 7.5 standard deviations in the 2009 data, is localized to the northwestern rim of the remnant in a region of enhanced radio and X-ray emission. It has an intrinsic extent of 0.23^{\circ} \pm 0.03^{\circ} (stat)+0.04^{\circ}_{-0.02}^{\circ}(sys) and its spectrum is well-characterized by a differential power law (dN/dE = N_0 \times (E/TeV)^{-\Gamma}) with a photon index of {\Gamma} = 2.37 \pm 0.14 (stat) \pm 0.20 (sys) and a flux normalization of N0 = 1.5 \pm 0.2 (stat) \pm 0.4(sys) \times 10^-12 ph TeV^{-1} cm^{-2} s^{-1}. This yields an integral flux of 5.2 \pm 0.8 (stat) \pm 1.4 (sys) \times 10^-12 ph cm^{-2} s^{-1} above 320 GeV, corresponding to 3.7% of the Crab Nebula flux. We consider the relationship of the TeV gamma-ray emission with the GeV gamma-ray emission seen from SNR G78.2+2.1 as well as that seen from a nearby cocoon of freshly accelerated cosmic rays. Multiple scenarios are considered as possible origins for the TeV gamma-ray emission, including hadronic particle acceleration at the supernova remnant shock., Comment: 18 pages, 5 figures, accepted for publication in ApJ
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- 2013
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18. Improved optoelectronic properties in CdSexTe1−x through controlled composition and short-range order
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Dumre, B.B., Szymanski, N.J., Adhikari, V., Khatri, I., Gall, D., and Khare, S.V.
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- 2019
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19. First principles investigation into the phase stability and enhanced hardness of TiN-ScN and TiN-YN alloys
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Adhikari, V., Szymanski, N.J., Khatri, I., Gall, D., and Khare, S.V.
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- 2019
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20. Discovery of TeV Gamma-ray Emission from CTA 1 by VERITAS
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Aliu, E., Archambault, S., Arlen, T., Aune, T., Beilicke, M., Benbow, W., Bouvier, A., Buckley, J. H., Bugaev, V., Cesarini, A., Ciupik, L., Collins-Hughes, E., Connolly, M. P., Cui, W., Dickherber, R., Duke, C., Dumm, J., Dwarkadas, V. V., Errando, M., Falcone, A., Federici, S., Feng, Q., Finley, J. P., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Gillanders, G. H., Godambe, S., Gotthelf, E. V., Griffin, S., Grube, J., Gyuk, G., Hanna, D., Holder, J., Hughes, G., Humensky, T. B., Kaaret, P., Kargaltsev, O., Karlsson, N., Khassen, Y., Kieda, D., Krawczynski, H., Krennrich, F., Lang, M. J., Lee, K., Madhavan, A. S, Maier, G., Majumdar, P., McArthur, S., McCann, A., Moriarty, P., Mukherjee, R., Nelson, T., de Bhroithe, A. O'Faolain, Ong, R. A., Orr, M., Otte, A. N., Park, N., Perkins, J. S., Pohl, M., Prokoph, H., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Roberts, M., Saxon, D. B., Schroedter, M., Sembroski, G. H., Slane, P., Smith, A. W., Staszak, D., Telezhinsky, I., Tesic, G., Theiling, M., Thibadeau, S., Tsurusaki, K., Tyler, J., Varlotta, A., Vassiliev, V. V., Vincent, S., Vivier, M., Wakely, S. P., Weekes, T. C., Weinstein, A., Welsing, R., Williams, D. A., and Zitzer, B.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We report the discovery of TeV gamma-ray emission coincident with the shell-type radio supernova remnant (SNR) CTA 1 using the VERITAS gamma-ray observatory. The source, VER J0006+729, was detected as a 6.5 standard deviation excess over background and shows an extended morphology, approximated by a two-dimensional Gaussian of semi-major (semi-minor) axis 0.30 degree (0.24 degree) and a centroid 5' from the Fermi gamma-ray pulsar PSR J0007+7303 and its X-ray pulsar wind nebula (PWN). The photon spectrum is well described by a power-law dN/dE = N_0 (E/3 TeV)^(-\Gamma), with a differential spectral index of \Gamma = 2.2 +- 0.2_stat +- 0.3_sys, and normalization N_0 = (9.1 +- 1.3_stat +- 1.7_sys) x 10^(-14) cm^(-2) s^(-1) TeV^(-1). The integral flux, F_\gamma = 4.0 x 10^(-12) erg cm^(-2) s^(-1) above 1 TeV, corresponds to 0.2% of the pulsar spin-down power at 1.4 kpc. The energetics, co-location with the SNR, and the relatively small extent of the TeV emission strongly argue for the PWN origin of the TeV photons. We consider the origin of the TeV emission in CTA 1., Comment: 10 pages, 9 figures, accepted for publication in ApJ
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- 2012
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21. Rapid TeV Gamma-Ray Flaring of BL Lacertae
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Arlen, T., Aune, T., Beilicke, M., Benbow, W., Bouvier, A., Buckley, J. H., Bugaev, V., Cesarini, A., Ciupik, L., Connolly, M. P., Cui, W., Dickherber, R., Dumm, J., Errando, M., Falcone, A., Federici, S., Feng, Q., Finley, J. P., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Griffin, S., Grube, J., Gyuk, G., Hanna, D., Holder, J., Humensky, T. B., Kaaret, P., Karlsson, N., Kertzman, M., Khassen, Y., Kieda, D., Krawczynski, H., Krennrich, F., Maier, G., Moriarty, P., Mukherjee, R., Nelson, T., de Bhroithe, A. O'Faolain, Ong, R. A., Orr, M., Park, N., Perkins, J. S., Pichel, A., Pohl, M., Prokoph, H., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Saxon, D. B., Schroedter, M., Sembroski, G. H., Staszak, D., Telezhinsky, I., Tesic, G., Theiling, M., Tsurusaki, K., Varlotta, A., Vincent, S., Wakely, S. P., Weekes, T. C., Weinstein, A., Welsing, R., Williams, D. A., Zitzer, B., Jorstad, S. G., MacDonald, N. R., Marscher, A. P., Smith, P. S., Walker, R. C., Hovatta, T., Richards, J., Max-Moerbeck, W., Readhead, A., Lister, M. L., Kovalev, Y. Y., Pushkarev, A. B., Gurwell, M. A., Lahteenmaki, A., Nieppola, E., Tornikoski, M., and Jarvela, E.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We report on the detection of a very rapid TeV gamma-ray flare from BL Lacertae on 2011 June 28 with the Very Energetic Radiation Imaging Telescope Array System (VERITAS). The flaring activity was observed during a 34.6-minute exposure, when the integral flux above 200 GeV reached $(3.4\pm0.6) \times 10^{-6} \;\text{photons}\;\text{m}^{-2}\text{s}^{-1}$, roughly 125% of the Crab Nebula flux measured by VERITAS. The light curve indicates that the observations missed the rising phase of the flare but covered a significant portion of the decaying phase. The exponential decay time was determined to be $13\pm4$ minutes, making it one of the most rapid gamma-ray flares seen from a TeV blazar. The gamma-ray spectrum of BL Lacertae during the flare was soft, with a photon index of $3.6\pm 0.4$, which is in agreement with the measurement made previously by MAGIC in a lower flaring state. Contemporaneous radio observations of the source with the Very Long Baseline Array (VLBA) revealed the emergence of a new, superluminal component from the core around the time of the TeV gamma-ray flare, accompanied by changes in the optical polarization angle. Changes in flux also appear to have occurred at optical, UV, and GeV gamma-ray wavelengths at the time of the flare, although they are difficult to quantify precisely due to sparse coverage. A strong flare was seen at radio wavelengths roughly four months later, which might be related to the gamma-ray flaring activities. We discuss the implications of these multiwavelength results., Comment: Accepted for publication in The Astrophysical Journal
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22. VERITAS Observations of Six Bright, Hard-Spectrum Fermi-LAT Blazars
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Aliu, E., Archambault, S., Arlen, T., Aune, T., Beilicke, M., Benbow, W., Bottcher, M., Bouvier, A., Buckley, J. H., Bugaev, V., Cesarini, A., Ciupik, L., Collins-Hughes, E., Connolly, M. P., Cui, W., Dickherber, R., Duke, C., Dumm, J., Errando, M., Falcone, A., Federici, S., Feng, Q., Finley, J. P., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Godambe, S., Griffin, S., Grube, J., Gyuk, G., Hanna, D., Holder, J., Huan, H., Kaaret, P., Karlsson, N., Khassen, Y., Kieda, D., Krawczynski, H., Krennrich, F., Lee, K., Madhavan, A. S, Maier, G., Majumdar, P., McArthur, S., McCann, A., Moriarty, P., Mukherjee, R., Nelson, T., de Bhroithe, A. O'Faolain, Ong, R. A., Orr, M., Otte, A. N., Park, N., Perkins, J. S., Pichel, A., Pohl, M., Prokoph, H., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Saxon, D. B., Sembroski, G. H., Staszak, D., Telezhinsky, I., Tesic, G., Theiling, M., Thibadeau, S., Tsurusaki, K., Varlotta, A., Vassiliev, V. V., Vincent, S., Vivier, M., Wakely, S. P., Weekes, T. C., Weinstein, A., Welsing, R., Williams, D. A., Zitzer, B., Fortin, P., Horan, D., Fumagalli, M., Kaplan, K., and Prochaska, J. X.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We report on VERITAS very-high-energy (VHE; E>100 GeV) observations of six blazars selected from the Fermi Large Area Telescope First Source Catalog (1FGL). The gamma-ray emission from 1FGL sources was extrapolated up to the VHE band, taking gamma-ray absorption by the extragalactic background light into account. This allowed the selection of six bright, hard-spectrum blazars that were good candidate TeV emitters. Spectroscopic redshift measurements were attempted with the Keck Telescope for the targets without Sloan Digital Sky Survey (SDSS) spectroscopic data. No VHE emission is detected during the observations of the six sources described here. Corresponding TeV upper limits are presented, along with contemporaneous Fermi observations and non-concurrent Swift UVOT and XRT data. The blazar broadband spectral energy distributions (SEDs) are assembled and modeled with a single-zone synchrotron self-Compton model. The SED built for each of the six blazars show a synchrotron peak bordering between the intermediate- and high-spectrum-peak classifications, with four of the six resulting in particle-dominated emission regions.
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- 2012
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23. Search for a correlation between very-high-energy gamma rays and giant radio pulses in the Crab pulsar
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Aliu, E., Archambault, S., Arlen, T., Aune, T., Beilicke, M., Benbow, W., Bouvier, A., Buckley, J. H., Bugaev, V., Byrum, K., Cesarini, A., Ciupik, L., Collins-Hughes, E., Connolly, M. P., Cui, W., Dickherber, R., Duke, C., Dumm, J., Falcone, A., Federici, S., Feng, Q., Finley, J. P., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Gillanders, G. H., Godambe, S., Griffin, S., Grube, J., Gyuk, G., Hanna, D., Holder, J., Huan, H., Hughes, G., Humensky, T. B., Kaaret, P., Karlsson, N., Khassen, Y., Kieda, D., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Lee, K., Lyutikov, M., Madhavan, A. S, Maier, G., Majumdar, P., McArthur, S., McCann, A., Moriarty, P., Mukherjee, R., Nelson, T., de Bhroithe, A. O'Faolain, Ong, R. A., Orr, M., Otte, A. N., Park, N., Perkins, J. S., Pohl, M., Prokoph, H., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Saxon, D. B., Schroedter, M., Sembroski, G. H., Senturk, G. D., Smith, A. W., Staszak, D., Telezhinsky, I., Tesic, G., Theiling, M., Thibadeau, S., Tsurusaki, K., Varlotta, A., Vincent, S., Vivier, M., Wagner, R. G., Wakely, S. P., Weekes, T. C., Weinstein, A., Welsing, R., Williams, D. A., Zitzer, B., and Kondratiev, V.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We present the results of a joint observational campaign between the Green Bank radio telescope and the VERITAS gamma-ray telescope, which searched for a correlation between the emission of very-high-energy (VHE) gamma rays ($E_{\gamma} >$ 150 GeV) and Giant Radio Pulses (GRPs) from the Crab pulsar at 8.9 GHz. A total of 15366 GRPs were recorded during 11.6 hours of simultaneous observations, which were made across four nights in December 2008 and in November and December 2009. We searched for an enhancement of the pulsed gamma-ray emission within time windows placed around the arrival time of the GRP events. In total, 8 different time windows with durations ranging from 0.033 ms to 72 s were positioned at three different locations relative to the GRP to search for enhanced gamma-ray emission which lagged, led, or was concurrent with, the GRP event. Further, we performed separate searches on main pulse GRPs and interpulse GRPs and on the most energetic GRPs in our data sample. No significant enhancement of pulsed VHE emission was found in any of the preformed searches. We set upper limits of 5-10 times the average VHE flux of the Crab pulsar on the flux simultaneous with interpulse GRPs on single-rotation-period time scales. On $\sim$8-second time scales around interpulse GRPs, we set an upper limit of 2-3 times the average VHE flux. Within the framework of recent models for pulsed VHE emission from the Crab pulsar, the expected VHE-GRP emission correlations are below the derived limits., Comment: 12 pages, 12 figures, To appear in The Astrophysical Journal
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- 2012
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24. Constraints on Cosmic Rays, Magnetic Fields, and Dark Matter from Gamma-Ray Observations of the Coma Cluster of Galaxies with VERITAS and Fermi
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Arlen, T., Aune, T., Beilicke, M., Benbow, W., Bouvier, A., Buckley, J. H., Bugaev, V., Byrum, K., Cannon, A., Cesarini, A., Ciupik, L., Collins-Hughes, E., Connolly, M. P., Cui, W., Dickherber, R., Dumm, J., Falcone, A., Federici, S., Feng, Q., Finley, J. P., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Godambe, S., Griffin, S., Grube, J., Gyuk, G., Holder, J., Huan, H., Hughes, G., Humensky, T. B., Imran, A., Kaaret, P., Karlsson, N., Kertzman, M., Khassen, Y., Kieda, D., Krawczynski, H., Krennrich, F., Lee, K., Madhavan, A. S, Maier, G., Majumdar, P., McArthur, S., McCann, A., Moriarty, P., Mukherjee, R., Nelson, T., de Bhróithe, A. O'Faoláin, Ong, R. A., Orr, M., Otte, A. N., Park, N., Perkins, J. S., Pohl, M., Prokoph, H., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Ruppel, J., Saxon, D. B., Schroedter, M., Sembroski, G. H., Skole, C., Smith, A. W., Telezhinsky, I., Tešić, G., Theiling, M., Thibadeau, S., Tsurusaki, K., Varlotta, A., Vivier, M., Wakely, S. P., Ward, J. E., Weinstein, A., Welsing, R., Williams, D. A., Zitzer, B., Pfrommer, C., and Pinzke, A.
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Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
Observations of radio halos and relics in galaxy clusters indicate efficient electron acceleration. Protons should likewise be accelerated, suggesting that clusters may also be sources of very high-energy (VHE; E>100 GeV) gamma-ray emission. We report here on VHE gamma-ray observations of the Coma galaxy cluster with the VERITAS array of imaging Cherenkov telescopes, with complementing Fermi-LAT observations at GeV energies. No significant gamma-ray emission from the Coma cluster was detected. Integral flux upper limits at the 99% confidence level were measured to be on the order of (2-5)*10^-8\ ph. m^-2 s^-1 (VERITAS, >220 GeV} and ~2*10^-6 ph. m^-2 s^-1 (Fermi, 1-3 GeV), respectively. We use the gamma-ray upper limits to constrain CRs and magnetic fields in Coma. Using an analytical approach, the CR-to-thermal pressure ratio is constrained to be < 16% from VERITAS data and < 1.7% from Fermi data (averaged within the virial radius). These upper limits are starting to constrain the CR physics in self-consistent cosmological cluster simulations and cap the maximum CR acceleration efficiency at structure formation shocks to be <50%. Assuming that the radio-emitting electrons of the Coma halo result from hadronic CR interactions, the observations imply a lower limit on the central magnetic field in Coma of (2 - 5.5) muG, depending on the radial magnetic-field profile and on the gamma-ray spectral index. Since these values are below those inferred by Faraday rotation measurements in Coma (for most of the parameter space), this {renders} the hadronic model a very plausible explanation of the Coma radio halo. Finally, since galaxy clusters are dark-matter (DM) dominated, the VERITAS upper limits have been used to place constraints on the thermally-averaged product of the total self-annihilation cross section and the relative velocity of the DM particles, <\sigma v>. (abr.), Comment: ApJ in press
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25. Multiwavelength observations of the AGN 1ES 0414+009 with VERITAS, Fermi-LAT, Swift-XRT, and MDM
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Aliu, E., Archambault, S., Arlen, T., Aune, T., Beilicke, M., Benbow, W., Bottcher, M., Bouvier, A., Bugaev, V., Cannon, A., Cesarini, A., Ciupik, L., Collins-Hughes, E., Connolly, M. P., Cui, W., Dickherber, R., Dumm, J., Errando, M., Falcone, A., Federici, S., Feng, Q., Finley, J. P., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Godambe, S., Griffin, S., Grube, J., Gyuk, G., Hanna, D., Huan, H., Hughes, G., Hui, C. M., Imran, A., Jameil, O., Kaaret, P., Karlsson, N., Kertzman, M., Kerr, J., Khassen, Y., Kieda, D., Krawczynski, H., Krennrich, F., Lang, M. J., Lee, K., Madhavan, A. S., Majumdar, P., McArthur, S., McCann, A., Moriarty, P., Mukherjee, R., Nelson, T., de Bhroithe, A. O'Faolain, Ong, R. A., Orr, M., Otte, A. N., Park, N., Perkins, J. S., Pichel, A., Pohl, M., Quinn, J., Ragan, K., Reynolds, P. T., Roache, E., Ruppel, J., Saxon, D. B., Schroedter, M., Sembroski, G. H., Senturk, G. D., Smith, A. W., Staszak, D., Stroh, M., Telezhinsky, I., Tesic, G., Theiling, M., Thibadeau, S., Tsurusaki, K., Varlotta, A., Vassiliev, V. V., Vivier, M., Wakely, S. P., Ward, J. E., Weinstein, A., Welsing, R., Williams, D. A., and Zitzer, B.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We present observations of the BL Lac object 1ES 0414+009 in the >200 GeV gamma-ray band by the VERITAS array of Cherenkov telescopes. 1ES 0414+009 was observed by VERITAS between January 2008 and February 2011, resulting in 56.2 hours of good quality pointed observations. These observations resulted in a detection of 822 events from the source corresponding to a statistical significance of 6.4 standard deviations (6.4 sigma) above the background. The source flux, showing no evidence for variability, is measured as 5.2 +/- 1.1_stat +/- 2.6_sys * 10^-12 photons cm^-2 s^-1 above 200 GeV, equivalent to approximately 2% of the Crab Nebula flux above this energy. The differential photon spectrum from 230 GeV to 850 GeV is well fit by a power law with an photon index of Gamma 3.4 +/- 0.5_stat +/- 0.3_sys and a flux normalization of 1.6 +/- 0.3_stat +/- 0.8_sys * 10^-11 photons cm^-2 s^-1 at 300 GeV. We also present multiwavelength results taken in the optical (MDM), X-ray (Swift-XRT), and GeV (Fermi-LAT) bands and use these results to construct a broadband spectral energy distribution (SED). Modeling of this SED indicates that homogenous one-zone leptonic scenarios are not adequate to describe emission from the system, with a lepto-hadronic model providing a better fit to the data., Comment: Accepted for publication in The Astrophysical Journal
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- 2012
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26. VERITAS Observations of the Nova in V407 Cygni
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Aliu, E., Archambault, S., Arlen, T., Aune, T., Beilicke, M., Benbow, W., Bouvier, A., Bradbury, S. M., Buckley, J. H., Bugaev, V., Byrum, K., Cannon, A., Cesarini, A., Ciupik, L., Collins-Hughes, E., Connolly, M. P., Cui, W., Decerprit, G., Dickherber, R., Duke, C., Dumm, J., Dwarkadas, V. V., Errando, M., Falcone, A., Feng, Q., Finley, J. P., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Godambe, S., Griffin, S., Grube, J., Gyuk, G., Hanna, D., Holder, J., Huan, H., Hughes, G., Humensky, T. B., Kaaret, P., Karlsson, N., Kertzman, M., Khassen, Y., Kieda, D., Krawczynski, H., Krennrich, F., Lang, M. J., Lee, K., Maier, G., Majumdar, P., McArthur, S., McCann, A., Millis, J., Moriarty, P., Mukherjee, R., Nuñez, P. D, Ong, R. A., Orr, M., Otte, A. N., Pandel, D., Park, N., Perkins, J. S., Pohl, M., Prokoph, H., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Rose, H. J., Ruppel, J., Saxon, D. B., Schroedter, M., Sembroski, G. H., Skole, C., Smith, A. W., Staszak, D., Telezhinsky, I., Tešić, G., Theiling, M., Thibadeau, S., Tsurusaki, K., Tyler, J., Varlotta, A., Vincent, S., Vivier, M., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Welsing, R., Williams, D. A., and Zitzer, B.
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Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Astrophysics of Galaxies - Abstract
We report on very high energy (E > 100 GeV) gamma-ray observations of V407 Cygni, a symbiotic binary that underwent a nova outburst producing 0.1-10 GeV gamma rays during 2010 March 10-26. Observations were made with the Very Energetic Radiation Imaging Telescope Array System during 2010 March 19-26 at relatively large zenith angles, due to the position of V407 Cyg. An improved reconstruction technique for large zenith angle observations is presented and used to analyze the data. We do not detect V407 Cygni and place a differential upper limit on the flux at 1.6 TeV of 2.3 \times 10^(-12) erg cm^(-2) s^(-1) (at the 95% confidence level). When considered jointly with data from Fermi-LAT, this result places limits on the acceleration of very high energy particles in the nova., Comment: 17 pages, 4 figures, accepted for publication in ApJ
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- 2012
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27. Discovery of High-energy and Very High Energy Gamma-ray Emission from the Blazar RBS 0413
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VERITAS Collaboration, Aliu, E., Archambault, S., Arlen, T., Aune, T., Beilicke, M., Benbow, W., Boettcher, M., Bouvier, A., Bradbury, S. M., Buckley, J. H., Bugaev, V., Byrum, K., Cannon, A., Cesarini, A., Ciupik, L., Collins-Hughes, E., Connolly, M. P., Coppi, P., Cui, W., Decerprit, G., Dickherber, R., Dumm, J., Errando, M., Falcone, A., Feng, Q., Finley, J. P., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Godambe, S., Griffin, S., Grube, J., Gyuk, G., Hanna, D., Hawkins, K., Holder, J., Huan, H., Hughes, G., Humensky, T. B., Kaaret, P., Karlsson, N., Kertzman, M., Khassen, Y., Kieda, D., Krawczynski, H., Krennrich, F., Lang, M. J., Lee, K., Madhavan, A. S, Maier, G., Majumdar, P., McArthur, S., McCann, A., Moriarty, P., Mukherjee, R., Ong, R. A., Orr, M., Otte, A. N., Palma, N., Park, N., Perkins, J. S., Pichel, A., Pohl, M., Prokoph, H., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Rose, H. J., Ruppel, J., Saxon, D. B., Schroedter, M., Sembroski, G. H., Senturk, G. D., Smith, A. W., Staszak, D., Telezhinsky, I., Tesic, G., Theiling, M., Thibadeau, S., Tsurusaki, K., Varlotta, A., Vivier, M., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Williams, D. A., Zitzer, B., Fortin, P., and Horan, D.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We report on the discovery of high-energy (HE; E > 0.1 GeV) and very high-energy (VHE; E > 100 GeV) gamma-ray emission from the high-frequency-peaked BL Lac object RBS 0413. VERITAS, a ground-based gamma-ray observatory, detected VHE gamma rays from RBS 0413 with a statistical significance of 5.5 standard deviations (sigma) and a gamma-ray flux of (1.5 \pm 0.6stat \pm 0.7syst) \times 10^(-8) photons m^(-2) s^(-1) (\sim 1% of the Crab Nebula flux) above 250 GeV. The observed spectrum can be described by a power law with a photon index of 3.18 \pm 0.68stat \pm 0.30syst. Contemporaneous observations with the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope detected HE gamma rays from RBS 0413 with a statistical significance of more than 9 sigma, a power-law photon index of 1.57 \pm 0.12stat +0.11sys -0.12sys and a gamma-ray flux between 300 MeV and 300 GeV of (1.64 \pm 0.43stat +0.31sys -0.22sys) \times 10^(-5) photons m^(-2) s^(-1). We present the results from Fermi-LAT and VERITAS, including a spectral energy distribution modeling of the gamma-ray, quasi-simultaneous X-ray (Swift-XRT), ultraviolet (Swift-UVOT) and R-band optical (MDM) data. We find that, if conditions close to equipartition are required, both the combined synchrotron self-Compton/external-Compton and the lepto-hadronic models are preferred over a pure synchrotron self-Compton model., Comment: 14 pages, 3 figures, accepted to ApJ, corresponding author: G. D. Senturk
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28. VERITAS Deep Observations of the Dwarf Spheroidal Galaxy Segue 1
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Aliu, E., Archambault, S., Arlen, T., Aune, T., Beilicke, M., Benbow, W., Bouvier, A., Bradbury, S. M., Buckley, J. H., Bugaev, V., Byrum, K., Cannon, A., Cesarini, A., Christiansen, J. L., Ciupik, L., Collins-Hughes, E., Connolly, M. P., Cui, W., Decerprit, G., Dickherber, R., Dumm, J., Errando, M., Falcone, A., Feng, Q., Ferrer, F., Finley, J. P., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Godambe, S., Griffin, S., Grube, J., Gyuk, G., Hanna, D., Holder, J., Huan, H., Hughes, G., Humensky, T. B., Kaaret, P., Karlsson, N., Kertzman, M., Khassen, Y., Kieda, D., Krawczynski, H., Krennrich, F., Lee, K., Madhavan, A. S, Maier, G., Majumdar, P., McArthur, S., McCann, A., Moriarty, P., Mukherjee, R., Ong, R. A., Orr, M., Otte, A. N., Park, N., Perkins, J. S., Pohl, M., Prokoph, H., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Rose, H. J., Ruppel, J., Saxon, D. B., Schroedter, M., Sembroski, G. H., Senturk, G. D., Skole, C., Smith, A. W., Staszak, D., Telezhinsky, I., Tesic, G., Theiling, M., Thibadeau, S., Tsurusaki, K., Varlotta, A., Vassiliev, V. V., Vincent, S., Vivier, M., Wagner, R. G., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Williams, D. A., and Zitzer, B.
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Astrophysics - High Energy Astrophysical Phenomena ,High Energy Physics - Experiment - Abstract
The VERITAS array of Cherenkov telescopes has carried out a deep observational program on the nearby dwarf spheroidal galaxy Segue 1. We report on the results of nearly 48 hours of good quality selected data, taken between January 2010 and May 2011. No significant $\gamma$-ray emission is detected at the nominal position of Segue 1, and upper limits on the integrated flux are derived. According to recent studies, Segue 1 is the most dark matter-dominated dwarf spheroidal galaxy currently known. We derive stringent bounds on various annihilating and decaying dark matter particle models. The upper limits on the velocity-weighted annihilation cross-section are $\mathrm{<\sigma v >^{95% CL} \lesssim 10^{-23} cm^{3} s^{-1}}$, improving our limits from previous observations of dwarf spheroidal galaxies by at least a factor of two for dark matter particle masses $\mathrm{m_{\chi}\gtrsim 300 GeV}$. The lower limits on the decay lifetime are at the level of $\mathrm{\tau^{95% CL} \gtrsim 10^{24} s}$. Finally, we address the interpretation of the cosmic ray lepton anomalies measured by ATIC and PAMELA in terms of dark matter annihilation, and show that the VERITAS observations of Segue 1 disfavor such a scenario., Comment: Added recently published erratum at the end of the original article
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- 2012
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29. VERITAS Observations of day-scale flaring of M87 in 2010 April
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Aliu, E., Arlen, T., Aune, T., Beilicke, M., Benbow, W., Bouvier, A., Bradbury, S. M., Buckley, J. H., Bugaev, V., Byrum, K., Cannon, A., Cesarini, A., Ciupik, L., Collins-Hughes, E., Connolly, M. P., Cui, W., Dickherber, R., Duke, C., Errando, M., Falcone, A., Finley, J. P., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Godambe, S., Griffin, S., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Holder, J., Huan, H., Hughes, G., Hui, C. M., Humensky, T. B., Imran, A., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Madhavan, A. S, Maier, G., Majumdar, P., McArthur, S., McCann, A., Moriarty, P., Mukherjee, R., Nunez, P. D, Ong, R. A., Orr, M., Otte, A. N., Park, N., Perkins, J. S., Pichel, A., Pohl, M., Prokoph, H., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Rose, H. J., Ruppel, J., Saxon, D. B., Schroedter, M., Sembroski, G. H., Şentürk, G. D., Skole, C., Staszak, D., Tešić, G., Theiling, M., Thibadeau, S., Tsurusaki, K., Tyler, J., Varlotta, A., Vassiliev, V. V., Vincent, S., Vivier, M., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Williams, D. A., and Zitzer, B.
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Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
VERITAS has been monitoring the very-high-energy (VHE; >100GeV) 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 350GeV. In 2010 April, VERITAS detected a flare from M87 with peak flux of (2.71 +- 0.68) X 10^{-11} cm^{-2} s^{-1} for E>350GeV. 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^{+0.22}_{-0.15} 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 M87 and the constraints they provide on the physical size of the emitting region., Comment: Accepted for publication in ApJ; 17 pages, 5 figures; Corresponding author: C. M. Hui
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- 2011
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30. The 2010 very high energy gamma-ray flare & 10 years of multi-wavelength observations of M 87
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Collaboration, The H. E. S. S., Abramowski, A., Acero, F., Aharonian, F., Akhperjanian, A. G., Anton, G., Balzer, A., Barnacka, A., de Almeida, U. Barres, Becherini, Y., Becker, J., Behera, B., Bernlöhr, K., Birsin, E., Biteau, J., Bochow, A., Boisson, C., Bolmont, J., Bordas, P., Brucker, J., Brun, F., Brun, P., Bulik, T., Büsching, I., Carrigan, S., Casanova, S., Cerruti, M., Chadwick, P. M., Charbonnier, A., Chaves, R. C. G., Cheesebrough, A., Clapson, A. C., Coignet, G., Cologna, G., Conrad, J., Dalton, M., Daniel, M. K., Davids, I. D., Degrange, B., Deil, C., Dickinson, H. J., Djannati-Ataï, A., Domainko, W., Drury, L. O'C., Dubus, G., Dutson, K., Dyks, J., Dyrda, M., Egberts, K., Eger, P., Espigat, P., Fallon, L., Farnier, C., Fegan, S., Feinstein, F., Fernandes, M. V., Fiasson, A., Fontaine, G., Förster, A., Füßling, M., Gallant, Y. A., Gast, H., Gérard, L., Gerbig, D., Giebels, B., Glicenstein, J. F., Glück, B., Goret, P., Göring, D., Häffner, S., Hague, J. D., Hampf, D., Hauser, M., Heinz, S., Heinzelmann, G., Henri, G., Hermann, G., Hinton, J. A., Hoffmann, A., Hofmann, W., Hofverberg, P., Holler, M., Horns, D., Jacholkowska, A., de Jager, O. C., Jahn, C., Jamrozy, M., Jung, I., Kastendieck, M. A., Katarzyński, K., Katz, U., Kaufmann, S., Keogh, D., Khangulyan, D., Khélifi, B., Klochkov, D., Kluźniak, W., Kneiske, T., Komin, Nu., Kosack, K., Kossakowski, R., Laffon, H., Lamanna, G., Lennarz, D., Lohse, T., Lopatin, A., Lu, C. -C., Marandon, V., Marcowith, A., Masbou, J., Maurin, D., Maxted, N., Mayer, M., McComb, T. J. L., Medina, M. C., Méhault, J., Moderski, R., Moulin, E., Naumann, C. L., Naumann-Godo, M., de Naurois, M., Nedbal, D., Nekrassov, D., Nguyen, N., Nicholas, B., Niemiec, J., Nolan, S. J., Ohm, S., Wilhelmi, E. de Oña, Opitz, B., Ostrowski, M., Oya, I., Panter, M., Arribas, M. Paz, Pedaletti, G., Pelletier, G., Petrucci, P. -O., Pita, S., Pühlhofer, G., Punch, M., Quirrenbach, A., Raue, M., Rayner, S. M., Reimer, A., Reimer, O., Renaud, M., Reyes, R. de los, Rieger, F., Ripken, J., Rob, L., Rosier-Lees, S., Rowell, G., Rudak, B., Rulten, C. B., Ruppel, J., Sahakian, V., Sanchez, D. A., Santangelo, A., Schlickeiser, R., Schöck, F. M., Schulz, A., Schwanke, U., Schwarzburg, S., Schwemmer, S., Sheidaei, F., Skilton, J. L., Sol, H., Spengler, G., Stawarz, Ł., Steenkamp, R., Stegmann, C., Stinzing, F., Stycz, K., Sushch, I., Szostek, A., Tavernet, J. -P., Terrier, R., Tluczykont, M., Valerius, K., van Eldik, C., Vasileiadis, G., Venter, C., Vialle, J. P., Viana, A., Vincent, P., Völk, H. J., Volpe, F., Vorobiov, S., Vorster, M., Wagner, S. J., Ward, M., White, R., Wierzcholska, A., Zacharias, M., Zajczyk, A., Zdziarski, A. A., Zech, A., Zechlin, H. -S., Collaboration, The MAGIC, Aleksić, J., Antonelli, L. A., Antoranz, P., Backes, M., Barrio, J. A., Bastieri, D., González, J. Becerra, Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Boller, A., Bonnoli, G., Tridon, D. Borla, Braun, I., Bretz, T., Cañellas, A., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Cossio, L., Covino, S., Dazzi, F., De Angelis, A., del Pozo, E. De Cea, De Lotto, B., Mendez, C. Delgado, Ortega, A. Diago, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Elsaesser, D., Ferenc, D., Fonseca, M. V., Font, L., Fruck, C., López, R. J. García, Garczarczyk, M., Garrido, D., Giavitto, G., Godinović, N., Hadasch, D., Häfner, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Huber, B., Jogler, T., Klepser, S., Krähenbühl, T., Krause, J., La Barbera, A., Lelas, D., Leonardo, E., Lindfors, E., Lombardi, S., López, M., Lorenz, E., Makariev, M., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Miyamoto, H., Moldón, J., Moralejo, A., Munar, P., Nieto, D., Nilsson, K., Orito, R., Paneque, D., Paoletti, R., Pardo, S., Paredes, J. M., Partini, S., Pasanen, M., Pauss, F., Perez-Torres, M. A., Persic, M., Peruzzo, L., Pilia, M., Pochon, J., Prada, F., Moroni, P. G. Prada, Prandini, E., Puljak, I., Reichardt, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rügamer, S., Saggion, A., Saito, K., Saito, T. Y., Salvati, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shayduk, M., Shore, S. N., Sillanpää, A., Sitarek, J., Sobczynska, D., Spanier, F., Spiro, S., Stamerra, A., Steinke, B., Storz, J., Strah, N., Surić, T., Takalo, L., Takami, H., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Thom, M., Tibolla, O., Torres, D. F., Treves, A., Vankov, H., Vogler, P., Wagner, R. M., Weitzel, Q., Zabalza, V., Zandanel, F., Zanin, R., Collaboration, The VERITAS, Arlen, T., Aune, T., Beilicke, M., Benbow, W., Bouvier, A., Bradbury, S. M., Buckley, J. H., Bugaev, V., Byrum, K., Cannon, A., Cesarini, A., Ciupik, L., Connolly, M. P., Cui, W., Dickherber, R., Duke, C., Errando, M., Falcone, A., Finley, J. P., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Godambe, S., Griffin, S., Grube, J., Gyuk, G., Hanna, D., Holder, J., Huan, H., Hui, C. M., Kaaret, P., Karlsson, N., Kertzman, M., Khassen, Y., Kieda, D., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Maier, G., McArthur, S., McCann, A., Moriarty, P., Mukherjee, R., Nuñez, P. D., Ong, R. A., Orr, M., Otte, A. N., Park, N., Perkins, J. S., Pichel, A., Pohl, M., Prokoph, H., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Rose, H. J., Schroedter, M., Sembroski, G. H., Şentürk, G. D., Telezhinsky, I., Tešić, G., Theiling, M., Thibadeau, S., Varlotta, A., Vassiliev, V. V., Vivier, M., Wakely, S. P., Weekes, T. C., Williams, D. A., Zitzer, B., Cara, M., Casadio, C., Cheung, C. C., McConville, W., Davies, F., Doi, A., Giovannini, G., Giroletti, M., Hada, K., Hardee, P., Harris, D. E., Junor, W., Kino, M., Lee, N. P., Ly, C., Madrid, J., Massaro, F., Mundell, C. G., Nagai, H., Perlman, E. S., Steele, I. A., Walker, R. C., and Wood, D. L.
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Astrophysics - Cosmology and Extragalactic Astrophysics - Abstract
Abridged: The giant radio galaxy M 87 with its proximity, famous jet, and very massive black hole 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 super-massive 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 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. 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 (~day), peak fluxes (Phi(>0.35 TeV) ~= (1-3) x 10^-11 ph cm^-2 s^-1), and VHE spectra. 43 GHz VLBA radio observations 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 ~3 days after the peak of the VHE gamma-ray emission reveal an enhanced flux from the core. The long-term (2001-2010) multi-wavelength light curve of M 87, spanning from radio to VHE and including data from HST, LT, VLA and EVN, 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., Comment: 19 pages, 5 figures; Corresponding authors: M. Raue, L. Stawarz, D. Mazin, P. Colin, C. M. Hui, M. Beilicke; Fig. 1 lightcurve data available online: http://www.desy.de/~mraue/m87/
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- 2011
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31. VERITAS Collaboration Contributions to the 32nd International Cosmic Ray Conference
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The VERITAS Collaboration, Aliu, E., Arlen, T., Aune, T., Beilicke, M., Benbow, W., Böttcher, M., Bouvier, A., Buckley, J. H., Bugaev, V., Byrum, K., Cannon, A., Cesarini, A., Christiansen, J. L., Ciupik, L., Collins-Hughes, E., Connolly, M. P., Cui, W., Dickherber, R., Duke, C., Dwarkadas, V. V., Errando, M., Falcone, A., Finley, J. P., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Gibbs, K., Gillanders, G. H., Godambe, S., Griffin, S., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Holder, J., Huan, H., Hughes, G., Hui, C. M., Humensky, T. B., Imran, A., Kaaret, P., Karlsson, N., Kertzman, M., Khassen, Y., Kieda, D., Krawczynski, H., Krennrich, F., Lang, M. J., Lyutikov, M., Madhavan, A. S, Maier, G., Majumdar, P., McArthur, S., McCann, A., McCutcheon, M., Moriarty, P., Mukherjee, R., Nunez, P. D, Ong, R. A., Orr, M., Otte, A. N., Park, N., Perkins, J. S., Pichel, A., Pizlo, F., Pohl, M., Prokoph, H., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Rovero, A. C., Ruppel, J., Sadun, A. C., Saxon, D. B., Schroedter, M., Sembroski, G. H., Şentürk, G. D., Smith, A. W., Staszak, D., Tešić, G., Theiling, M., Thibadeau, S., Tsurusaki, K., Tyler, J., Varlotta, A., Vassiliev, V. V., Vincent, S., Vivier, M., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Williams, D. A., and Zitzer, B.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
Compilation of papers contributed by the VERITAS Collaboration to the 32nd International Cosmic Ray Conference, held 11-18 August 2011 in Beijing, China., Comment: 1 html page. ICRC 2011, Beijing, China. A full list of authors and collaborating institutions can be found at http://veritas.sao.arizona.edu/conferences/authors?icrc2011
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- 2011
32. VERITAS: Status and Highlights
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Holder, J., Aliu, E., Arlen, T., Aune, T., Beilicke, M., Benbow, W., Böttcher, M., Bouvier, A., Buckley, J. H., Bugaev, V., Byrum, K., Cannon, A., Cesarini, A., Christiansen, J. L., Ciupik, L., Collins-Hughes, E., Connolly, M. P., Cui, W., Dickherber, R., Duke, C., Dwarkadas, V. V., Errando, M., Falcone, A., Finley, J. P., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Gibbs, K., Gillanders, G. H., Godambe, S., Griffin, S., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Huan, H., Hughes, G., Hui, C. M., Humensky, T. B., Imran, A., Kaaret, P., Karlsson, N., Kertzman, M., Khassen, Y., Kieda, D., Krawczynski, H., Krennrich, F., Lang, M. J., Lyutikov, M., Madhavan, A. S, Maier, G., Majumdar, P., McArthur, S., McCann, A., McCutcheon, M., Moriarty, P., Mukherjee, R., Nunez, P. D, Ong, R. A., Orr, M., Otte, A. N., Park, N., Perkins, J. S., Pichel, A., Pizlo, F., Pohl, M., Prokoph, H., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Rovero, A. C., Ruppel, J., Sadun, A. C., Saxon, D. B., Schroedter, M., Sembroski, G. H., Şentürk, G. D., Smith, A. W., Staszak, D., Tešić, G., Theiling, M., Thibadeau, S., Tsurusaki, K., Tyler, J., Varlotta, A., Vassiliev, V. V., Vincent, S., Vivier, M., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Williams, D. A., and Zitzer, B.
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Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Instrumentation and Methods for Astrophysics - Abstract
The VERITAS telescope array has been operating smoothly since 2007, and has detected gamma-ray emission above 100 GeV from 40 astrophysical sources. These include blazars, pulsar wind nebulae, supernova remnants, gamma-ray binary systems, a starburst galaxy, a radio galaxy, the Crab pulsar, and gamma-ray sources whose origin remains unidentified. In 2009, the array was reconfigured, greatly improving the sensitivity. We summarize the current status of the observatory, describe some of the scientific highlights since 2009, and outline plans for the future., Comment: Presented at the 32nd ICRC, Beijing, 2011
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33. Multiwavelength Observations of the Previously Unidentified Blazar RX J0648.7+1516
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Aliu, E., Aune, T., Beilicke, M., Benbow, W., Böttcher, M., Bouvier, A., Bradbury, S. M., Buckley, J. H., Bugaev, V., Cannon, A., Cesarini, A., Ciupik, L., Connolly, M. P., Cui, W., Decerprit, G., Dickherber, R., Duke, C., Errando, M., Falcone, A., Feng, Q., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Gillanders, G. H., Godambe, S., Griffin, S., Grube, J., Gyuk, G., Hanna, D., Hivick, B., Holder, J., Huan, H., Hughes, G., Hui, C. M., Humensky, T. B., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Krawczynski, H., Krennrich, F., Maier, G., Majumdar, P., McArthur, S., McCann, A., Moriarty, P., Mukherjee, R., Nelson, T., Ong, R. A., Orr, M., Otte, A. N., Park, N., Perkins, J. S., Pichel, A., Pohl, M., Prokoph, H., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Rose, H. J., Ruppel, J., Saxon, D. B., Sembroski, G. H., Skole, C., Smith, A. W., Staszak, D., Tesic, G., Theiling, M., Thibadeau, S., Tsurusaki, K., Tyler, J., Varlotta, A., Vassiliev, V. V., Wakely, S. P., Weekes, T. C., Weinstein, A., Williams, D. A., Zitzer, B., Ciprini, S., Fumagalli, M., Kaplan, K., Paneque, D., and Prochaska, J. X.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We report on the VERITAS discovery of very-high-energy (VHE) gamma- ray emission above 200 GeV from the high-frequency-peaked BL Lac object RXJ0648.7+1516 (GBJ0648+1516), associated with 1FGLJ0648.8+1516. The photon spectrum above 200 GeV is fit by a power law dN/dE = F0(E/E0)-{\Gamma} with a photon index {\Gamma} of 4.4 {\pm} 0.8stat {\pm}0.3syst and a flux normalization F0 of (2.3 {\pm}0.5stat {\pm} 1.2sys) {\times} 10-11 TeV-1cm-2s-1 with E0 = 300 GeV. No VHE vari- ability is detected during VERITAS observations of RXJ0648.7+1516 between 2010 March 4 and April 15. Following the VHE discovery, the optical identifica- tion and spectroscopic redshift were obtained using the Shane 3-m Telescope at the Lick Observatory, showing the unidentified object to be a BL Lac type with a redshift of z = 0.179. Broadband multiwavelength observations contemporaneous with the VERITAS exposure period can be used to sub-classify the blazar as a high-frequency-peaked BL Lac (HBL) object, including data from the MDM ob- servatory, Swift-UVOT and XRT, and continuous monitoring at photon energies above 1 GeV from the Fermi Large Area Telescope (LAT). We find that in the absence of undetected, high-energy rapid variability, the one-zone synchrotron self-Compton model (SSC) overproduces the high-energy gamma-ray emission measured by the Fermi-LAT over 2.3 years. The SED can be parameterized sat- isfactorily with an external-Compton or lepto-hadronic model, which have two and six additional free parameters, respectively, compared to the one-zone SSC model.
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34. VERITAS Observations of Gamma-Ray Bursts Detected by Swift
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VERITAS Collaboration, Acciari, V. A., Aliu, E., Arlen, T., Aune, T., Beilicke, M., Benbow, W., Bradbury, S. M., Buckley, J. H., Bugaev, V., Byrum, K., Cannon, A., Cesarini, A., Christiansen, J. L., Ciupik, L., Collins-Hughes, E., Connolly, M. P., Cui, W., Duke, C., Errando, M., Falcone, A., Finley, J. P., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Godambe, S., Griffin, S., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Holder, J., Hughes, G., Hui, C. M., Humensky, T. B., Jackson, D. J., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Krawczynski, H., Krennrich, F., Lang, M. J., Madhavan, A. S, Maier, G., McArthur, S., McCann, A., Moriarty, P., Newbold, M. D., Ong, R. A., Orr, M., Otte, A. N., Park, N., Perkins, J. S., Pohl, M., Prokoph, H., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Rose, H. J., Ruppel, J., Saxon, D. B., Schroedter, M., Sembroski, G. H., Şentürk, G. D., Smith, A. W., Staszak, D., Swordy, S. P., Tešić, G., Theiling, M., Thibadeau, S., Tsurusaki, K., Varlotta, A., Vassiliev, V. V., Vincent, S., Vivier, M., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Williams, D. A., and Wood, M.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We present the results of sixteen Swift-triggered GRB follow-up observations taken with the VERITAS telescope array from January, 2007 to June, 2009. The median energy threshold and response time of these observations was 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 time scale 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 (LAT) on-board the Fermi satellite. No significant 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 (EBL) 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., Comment: 11 pages, 6 figures
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35. Detection of Pulsed Gamma Rays Above 100 GeV from the Crab Pulsar
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VERITAS Collaboration, Aliu, E., Arlen, T., Aune, T., Beilicke, M., Benbow, W., Bouvier, A., Bradbury, S. M., Buckley, J. H., Bugaev, V., Byrum, K., Cannon, A., Cesarini, A., Christiansen, J. L., Ciupik, L., Collins-Hughes, E., Connolly, M. P., Cui, W., Dickherber, R., Duke, C., Errando, M., Falcone, A., Finley, J. P., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Gibbs, K., Gillanders, G. H., Godambe, S., Griffin, S., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Holder, J., Huan, H., Hughes, G., Hui, C. M., Humensky, T. B., Imran, A., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Krawczynski, H., Krennrich, F., Lang, M. J., Lyutikov, M., Madhavan, A. S, Maier, G., Majumdar, P., McArthur, S., McCann, A., McCutcheon, M., Moriarty, P., Mukherjee, R., Nuñez, P., Ong, R. A., Orr, M., Otte, A. N., Park, N., Perkins, J. S., Pizlo, F., Pohl, M., Prokoph, H., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Rose, J., Ruppel, J., Saxon, D. B., Schroedter, M., Sembroski, G. H., Şentürk, G. D., Smith, A. W., Staszak, D., Tešić, G., Theiling, M., Thibadeau, S., Tsurusaki, K., Tyler, J., Varlotta, A., Vassiliev, V. V., Vincent, S., Vivier, M., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Williams, D. A., and Zitzer, B.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We report the detection of pulsed gamma rays from the Crab pulsar at energies above 100 Gigaelectronvolts (GeV) with the VERITAS array of atmospheric Cherenkov telescopes. The detection cannot be explained on the basis of current pulsar models. The photon spectrum of pulsed emission between 100 Megaelectronvolts (MeV) and 400 GeV is described by a broken power law that is statistically preferred over a power law with an exponential cutoff. It is unlikely that the observation can be explained by invoking curvature radiation as the origin of the observed gamma rays above 100 GeV. Our findings require that these gamma rays be produced more than 10 stellar radii from the neutron star., Comment: 17 pages, corresponding authors: Nepomuk Otte nepomuk.otte@gmail.com; Andrew McCann mccann@hep.physics.mcgill.ca; Martin Schroedter schroedter@veritas.sao.arizona.edu
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- 2011
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36. VERITAS Observations of the Unusual Extragalactic Transient Swift J164449.3+573451
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Aliu, E., Arlen, T., Aune, T., Beilicke, M., Benbow, W., Böttcher, M., Bouvier, A., Bradbury, S. M., Buckley, J. H., Bugaev, V., Cannon, A., Cesarini, A., Ciupik, L., Collins-Hughes, E., Connolly, M. P., Cui, W., Dickherber, R., Errando, M., Falcone, A., Finley, J. P., Fortson, L., Furniss, A., Galante, N., Gall, D., Gillanders, G. H., Godambe, S., Griffin, S., Grube, J., Gyuk, G., Hanna, D., Holder, J., Huan, H., Hughes, G., Hui, C. M., Humensky, T. B., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Krawczynski, H., Krennrich, F., Madhavan, A. S, Maier, G., Majumdar, P., McArthur, S., McCann, A., Moriarty, P., Mukherjee, R., Ong, R. A., Orr, M., Otte, A. N., Park, N., Perkins, J. S., Pichel, A., Pohl, M., Prokoph, H., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Rose, H. J., Ruppel, J., Saxon, D. B., Schroedter, M., Sembroski, G. H., Skole, C., Smith, A. W., Staszak, D., Tešić, G., Theiling, M., Thibadeau, S., Tsurusaki, K., Tyler, J., Varlotta, A., Vincent, S., Vivier, M., Wakely, S. P., Ward, J. E., Weinstein, A., Weisgarber, T., and Williams, D. A.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We report on very-high-energy ($>$100 GeV) gamma-ray observations of Swift J164449.3+573451, an unusual transient object first detected by the {\it Swift} Observatory and later detected by multiple radio, optical and X-ray observatories. A total exposure of 28 hours was obtained on Swift J164449.3+573451 with VERITAS during 2011 March 28 -- April 15. We do not detect the source and place a differential upper limit on the emission at 500 GeV during these observations of $1.4 \times 10^{-12}$ erg cm$^{-2}$ s$^{-1}$ (99% confidence level). We also present time-resolved upper limits and use a flux limit averaged over the X-ray flaring period to constrain various emission scenarios that can accommodate both the radio-through-X-ray emission detected from the source and the lack of detection by VERITAS.
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- 2011
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37. Multiwavelength Observations of the VHE Blazar 1ES 2344+514
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Acciari, V. A., Aliu, E., Arlen, T., Aune, T., Beilicke, M., Benbow, W., Boltuch, D., Bugaev, V., Cannon, A., Ciupik, L., Cogan, P., Colin, P., Dickherber, R., Falcone, A., Fegan, S. J., Finley, J. P., Fortin, P., Fortson, L. F., Furniss, A., Gall, D., Gillanders, G. H., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Holder, J., Horan, D., Hui, C. M., Humensky, T. B., Imran, A., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Kildea, J., Konopelko, A., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Maier, G., Moriarty, P., Mukherjee, R., Ong, R. A., Otte, A. N., Pandel, D., Perkins, J. S., Pichel, A., Pohl, M., Quinn, J., Ragan, K., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Smith, A. W., Steele, D., Swordy, S. P., Theiling, M., Toner, J. A., Varlotta, A., Vassiliev, V. V., Vincent, S., Wagner, R., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Williams, D. A., Wissel, S., Wood, M., and Zitzer, B.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
Multiwavelength observations of the high-frequency-peaked blazar 1ES2344+514 were performed from 2007 October to 2008 January. The campaign represents the first contemporaneous data on the object at very high energy (VHE, E >100 GeV) {\gamma}-ray, X-ray, and UV energies. Observations with VERITAS in VHE {\gamma}-rays yield a strong detection of 20 {\sigma} with 633 excess events in a total exposure of 18.1 hours live-time. A strong VHE {\gamma}-ray flare on 2007 December 7 is measured at F(>300 GeV) = (6.76 \pm 0.62) \times 10-11 ph cm-2 s-1, corresponding to 48% of the Crab Nebula flux. Excluding this flaring episode, nightly variability at lower fluxes is observed with a time-averaged mean of F(>300 GeV) = (1.06 \pm 0.09) \times 10-11 ph cm-2 s-1 (7.6% of the Crab Nebula flux). The differential photon spectrum between 390 GeV and 8.3 TeV for the time-averaged observations excluding 2007 December 7 is well described by a power law with a photon index of {\Gamma} = 2.78 \pm 0.09stat \pm 0.15syst. Over the full period of VERITAS observations contemporaneous X-ray and UV data were taken with Swift and RXTE. The measured 2-10 keV flux ranged by a factor of ~7 during the campaign. On 2007 December 8 the highest ever observed X-ray flux from 1ES 2344+514 was measured by Swift XRT at a flux of F(2-10 keV) = (6.28 \pm 0.31) \times 10-11 erg cm-2 s-1. Evidence for a correlation between the X-ray flux and VHE {\gamma}-ray flux on nightly time-scales is indicated with a Pearson correlation coefficient of r = 0.60 \pm 0.11. Contemporaneous spectral energy distributions (SEDs) of 1ES 2344+514 are presented for two distinct flux states. A one-zone synchrotron self-Compton (SSC) model describes both SEDs using parameters consistent with previous SSC modeling of 1ES 2344+514 from non-contemporaneous observations., Comment: 13 pages, 7 figures, accepted by ApJ
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- 2011
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38. TeV and Multi-wavelength Observations of Mrk 421 in 2006-2008
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Acciari, V. A., Aliu, E., Arlen, T., Aune, T., Beilicke, M., Benbow, W., Boltuch, D., Bradbury, S. M., Buckley, J. H., Bugaev, V., Byrum, K., Cannon, A., Cesarini, A., Ciupik, L., Cui, W., Dickherber, R., Duke, C., Falcone, A., Finley, J. P., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Gillanders, G. H., Godambe, S., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Holder, J., Hui, C. M., Humensky, T. B., Imran, A., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Konopelko, A., Krawczynski, H., Krennrich, F., Lang, M. J., Maier, G., McArthur, S., McCutcheon, M., Moriarty, P., Ong, R. A., Otte, A. N., Ouellette, M., Pandel, D., Perkins, J. S., Pichel, A., Pohl, M., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Rose, H. J., Rovero, A. C., Schroedter, M., Sembroski, G. H., Senturk, G. Demet, Steele, D., Swordy, S. P., Theiling, M., Thibadeau, S., Varlotta, A., Vassiliev, V. V., Vincent, S., Wagner, R. G., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Williams, D. A., Wissel, S., Wood, M., Zitzer, B., Garson, A., Lee, K., Sadun, A. C., Carini, M., Barnaby, D., Cook, K., Maune, J., Pease, A., Smith, S., Walters, R., Berdyugin, A., Lindfors, E., Nilsson, K., Pasanen, M., Sainio, J., Sillanpaa, A., Takalo, L. O., Villforth, C., Montaruli, T., Baker, M., Lahteenmaki, A., Tornikoski, M., Hovatta, T., Nieppola, E., Aller, H. D., and Aller, M. F.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We report on TeV gamma-ray observations of the blazar Mrk 421 (redshift of 0.031) with the VERITAS observatory and the Whipple 10m Cherenkov telescope. The excellent sensitivity of VERITAS allowed us to sample the TeV gamma-ray fluxes and energy spectra with unprecedented accuracy where Mrk 421 was detected in each of the pointings. A total of 47.3 hrs of VERITAS and 96 hrs of Whipple 10m data were acquired between January 2006 and June 2008. We present the results of a study of the TeV gamma-ray energy spectra as a function of time, and for different flux levels. On May 2nd and 3rd, 2008, bright TeV gamma-ray flares were detected with fluxes reaching the level of 10 Crab. The TeV gamma-ray data were complemented with radio, optical, and X-ray observations, with flux variability found in all bands except for the radio waveband. The combination of the RXTE and Swift X-ray data reveal spectral hardening with increasing flux levels, often correlated with an increase of the source activity in TeV gamma-rays. Contemporaneous spectral energy distributions were generated for 18 nights, each of which are reasonably described by a one-zone SSC model., Comment: 30 pages, 12 figures, accepted by ApJ
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- 2011
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39. VERITAS Observations of the TeV Binary LS I +61 303 During 2008-2010
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Acciari, V. A., Aliu, E., Arlen, T., Aune, T., Beilicke, M., Benbow, W., Bradbury, S. M., Buckley, J. H., Bugaev, V., Byrum, K., Cannon, A., Cesarini, A., Ciupik, L., Collins-Hughes, E., Connolly, M. P., Cui, W., Dickherber, R., Duke, C., Errando, M., Falcone, A., Finley, J. P., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Gillanders, G. H., Godambe, S., Griffin, S., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Holder, J., Hughes, G., Hui, C. M., Humensky, T. B., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Maier, G., Majumdar, P., McArthur, S., McCann, A., Moriarty, P., Mukherjee, R., Ong, R. A., Orr, M., Otte, A. N., Park, N., Perkins, J. S., Pohl, M., Prokoph, H., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Rose, H. J., Ruppel, J., Saxon, D. B., Schroedter, M., Sembroski, G. H., Senturk, G. Demet, Smith, A. W., Staszak, D., Tesic, G., Theiling, M., Thibadeau, S., Tsurusaki, K., Varlotta, A., Vassiliev, V. V., Vincent, S., Vivier, M., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Williams, D. A., and Zitzer, B.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We present the results of observations of the TeV binary LS I +61 303 with the VERITAS telescope array between 2008 and 2010, at energies above 300 GeV. In the past, both ground-based gamma-ray telescopes VERITAS and MAGIC have reported detections of TeV emission near the apastron phases of the binary orbit. The observations presented here show no strong evidence for TeV emission during these orbital phases; however, during observations taken in late 2010, significant emission was detected from the source close to the phase of superior conjunction (much closer to periastron passage) at a 5.6 standard deviation (5.6 sigma) post-trials significance. In total, between October 2008 and December 2010 a total exposure of 64.5 hours was accumulated with VERITAS on LS I +61 303, resulting in an excess at the 3.3 sigma significance level for constant emission over the entire integrated dataset. The flux upper limits derived for emission during the previously reliably active TeV phases (i.e. close to apastron) are less than 5% of the Crab Nebula flux in the same energy range. This result stands in apparent contrast to previous observations by both MAGIC and VERITAS which detected the source during these phases at >10% of the Crab Nebula flux. During the two year span of observations, a large amount of X-ray data were also accrued on LS I +61 303 by the Swift X-ray Telescope (XRT) and the Rossi X-ray Timing Explorer Timing (RXTE) Proportional Counter Array (PCA). We find no evidence for a correlation between emission in the X-ray and TeV regimes during 20 directly overlapping observations. We also comment on data obtained contemporaneously by the Fermi Large Area Telescope (LAT)., Comment: Accepted for Publication in The Astrophysical Journal, 21 pages, 3 tables, 6 figures
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- 2011
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40. Gamma-ray observations of the Be/pulsar binary 1A 0535+262 during a giant X-ray outburst
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VERITAS collaboration, Acciari, V. A., Aliu, E., Araya, M., Arlen, T., Aune, T., Beilicke, M., Benbow, W., Bradbury, S. M., Buckley, J. H., Bugaev, V., Byrum, K., Cannon, A., Cesarini, A., Ciupik, L., Collins-Hughes, E., Cui, W., Dickherber, R., Duke, C., Falcone, A., Finley, J. P., Fortson, L., Furniss, A., Galante, N., Gall, D., Godambe, S., Griffin, S., Guenette, R., Gyuk, G., Hanna, D., Holder, J., Hughes, G., Hui, C. M., Humensky, T. B., Imran, A., Kaaret, P., Kertzman, M., Krawczynski, H., Krennrich, F., Madhavan, A. S., Maier, G., Majumdar, P., McArthur, S., Moriarty, P., Ong, R. A., Otte, A. N., Pandel, D., Park, N., Perkins, J. S., Pohl, M., Prokoph, H., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Rose, H. J., Saxon, D. B., Sembroski, G. H., Senturk, G. Demet, Smith, A. W., Tešić, G., Theiling, M., Thibadeau, S., Varlotta, A., Vincent, S., Vivier, M., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Weng, S., Williams, D. A., Wood, M., and Zitzer, B.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
Giant X-ray outbursts, with luminosities of about $ 10^{37}$ erg s$^{-1}$, are observed roughly every 5 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 (VHE; E$>$100 GeV) triggered by the X-ray outburst in December 2009. The observations started shortly after the onset of the outburst, and they provided comprehensive coverage of the episode, as well as the 111-day binary orbit. No VHE emission is evident at any time. We also examined data from the contemporaneous observations of 1A 0535+262 with the Fermi/LAT at high energy photons (HE; E$>$0.1 GeV) and failed to detect the source at GeV energies. The X-ray continua measured with the Swift/XRT and the RXTE/PCA can be well described by the combination of blackbody and Comptonized emission from thermal electrons. Therefore, the gamma-ray and X-ray observations suggest the absence of a significant population of non-thermal particles in the system. This distinguishes 1A~0535+262 from those Be X-ray binaries (such as PSR B1259--63 and LS I +61$^{\circ}$303) that have been detected at GeV--TeV energies. We discuss the implications of the results on theoretical models., Comment: 28 pages, 4 figures; accepted by The Astrophysical Journal updated references
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- 2011
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41. Discovery of TeV Gamma Ray Emission from Tycho's Supernova Remnant
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Acciari, V. A., Aliu, E., Arlen, T., Aune, T., Beilicke, M., Benbow, W., Bradbury, S. M., Buckley, J. H., Bugaev, V., Byrum, K., Cannon, A., Cesarini, A., Ciupik, L., Collins-Hughes, E., Cui, W., Dickherber, R., Duke, C., Errando, M., Finley, J. P., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Gillanders, G. H., Godambe, S., Griffin, S., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Holder, J., Hughes, J. P., Hui, C. M., Humensky, T. B., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Madhavan, A. S, Maier, G., Majumdar, P., McArthur, S., McCann, A., Moriarty, P., Mukherjee, R., Ong, R. A., Orr, M., Otte, A. N., Pandel, D., Park, N., Perkins, J. S., Pohl, M., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Rose, H. J., Saxon, D. B., Schroedter, M., Sembroski, G. H., Senturk, G. Demet, Slane, P., Smith, A. W., Tešić, G., Theiling, M., Thibadeau, S., Tsurusaki, K., Varlotta, A., Vassiliev, V. V., Vincent, S., Vivier, M., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Williams, D. A., Wood, M., and Zitzer, B.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We report the discovery of TeV gamma-ray emission from the Type Ia supernova remnant (SNR) G120.1+1.4, known as Tycho's supernova remnant. Observations performed in the period 2008-2010 with the VERITAS ground-based gamma-ray observatory reveal weak emission coming from the direction of the remnant, compatible with a point source located at $00^{\rm h} \ 25^{\rm m} \ 27.0^{\rm s},\ +64^{\circ} \ 10^{\prime} \ 50^{\prime\prime}$ (J2000). The TeV photon spectrum measured by VERITAS can be described with a power-law $dN/dE = C(E/3.42\;\textrm{TeV})^{-\Gamma}$ with $\Gamma = 1.95 \pm 0.51_{stat} \pm 0.30_{sys}$ and $C = (1.55 \pm 0.43_{stat} \pm 0.47_{sys}) \times 10^{-14}$ cm$^{-2}$s$^{-1}$TeV$^{-1}$. The integral flux above 1 TeV corresponds to $\sim 0.9%$ percent of the steady Crab Nebula emission above the same energy, making it one of the weakest sources yet detected in TeV gamma rays. We present both leptonic and hadronic models which can describe the data. The lowest magnetic field allowed in these models is $\sim 80 \mu$G, which may be interpreted as evidence for magnetic field amplification., Comment: 6 pages, 3 figures. Accepted in ApJL
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- 2011
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42. Spectral Energy Distribution of Markarian 501: Quiescent State vs. Extreme Outburst
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The VERITAS Collaboration, Acciari, V. A., Arlen, T., Aune, T., Beilicke, M., Benbow, W., Böttcher, M., Boltuch, D., Bradbury, S. M., Buckley, J. H., Bugaev, V., Cannon, A., Cesarini, A., Ciupik, L., Cui, W., Dickherber, R., Duke, C., Errando, M., Falcone, A., Finley, J. P., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Godambe, S., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Holder, J., Huang, D., Hui, C. M., Humensky, T. B., Imran, A., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Konopelko, A., Krawczynski, H., Krennrich, F., Madhavan, A. S, Maier, G., McArthur, S., McCann, A., Moriarty, P., Ong, R. A., Otte, A. N., Pandel, D., Perkins, J. S., Pichel, A., Pohl, M., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Rose, H. J., Schroedter, M., Sembroski, G. H., Steele, D., Swordy, S. P., Theiling, M., Thibadeau, S., Varlotta, A., Vassiliev, V. V., Vincent, S., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Williams, D. A., Wood, M., Zitzer, B., Collaboration, The MAGIC, Aleksić, J., Antonelli, L. A., Antoranz, P., Backes, M., Barrio, J. A., Bastieri, D., González, J. Becerra, Bednarek, W., Berdyugin, A., Berger, K., Bernardini, E., Biland, A., Blanch, O., Bock, R. K., Boller, A., Bonnoli, G., Bordas, P., Tridon, D. Borla, Bosch-Ramon, V., Bose, D., Braun, I., Bretz, T., Camara, M., Carmona, E., Carosi, A., Colin, P., Colombo, E., Contreras, J. L., Cortina, J., Covino, S., Dazzi, F., De Angelis, A., del Pozo, E. De Cea, De Lotto, B., De Maria, M., De Sabata, F., Mendez, C. Delgado, Ortega, A. Diago, Doert, M., Domínguez, A., Prester, D. Dominis, Dorner, D., Doro, M., Elsaesser, D., Ferenc, D., Fonseca, M. V., Font, L., López, R. J. García, Garczarczyk, M., Gaug, M., Giavitto, G., Godinović, N., Hadasch, D., Herrero, A., Hildebrand, D., Höhne-Mönch, D., Hose, J., Hrupec, D., Jogler, T., Klepser, S., Krähenbühl, T., Kranich, D., Krause, J., La Barbera, A., Leonardo, E., Lindfors, E., Lombardi, S., Longo, F., López, M., Lorenz, E., Majumdar, P., Makariev, M., Maneva, G., Mankuzhiyil, N., Mannheim, K., Maraschi, L., Mariotti, M., Martínez, M., Mazin, D., Meucci, M., Miranda, J. M., Mirzoyan, R., Miyamoto, H., Moldón, J., Moralejo, A., Nieto, D., Nilsson, K., Orito, R., Oya, I., Paoletti, R., Paredes, J. M., Partini, S., Pasanen, M., Pauss, F., Pegna, R. G., Perez-Torres, M. A., Persic, M., Peruzzo, L., Pochon, J., Prada, F., Moroni, P. G. Prada, Prandini, E., Puchades, N., Puljak, I., Reichardt, I., Reinthal, R., Rhode, W., Ribó, M., Rico, J., Rissi, M., Rügamer, S., Saggion, A., Saito, K., Saito, T. Y., Salvati, M., Sánchez-Conde, M., Satalecka, K., Scalzotto, V., Scapin, V., Schultz, C., Schweizer, T., Shayduk, M., Shore, S. N., Sierpowska-Bartosik, A., Sillanpää, A., Sitarek, J., Sobczynska, D., Spanier, F., Spiro, S., Stamerra, A., Steinke, B., Storz, J., Strah, N., Struebig, J. C., Suric, T., Takalo, L., Tavecchio, F., Temnikov, P., Terzić, T., Tescaro, D., Teshima, M., Torres, D. F., Vankov, H., Wagner, R. M., Weitzel, Q., Zabalza, V., Zandanel, F., Zanin, R., Paneque, D., and Hayashida, M.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
The very high energy (VHE; E > 100 GeV) blazar Markarian 501 has a well-studied history of extreme spectral variability and is an excellent laboratory for studying the physical processes within the jets of active galactic nuclei. However, there are few detailed multiwavelength studies of Markarian 501 during its quiescent state, due to its low luminosity. A short-term multiwavelength study of Markarian 501 was coordinated in March 2009, focusing around a multi-day observation with the Suzaku X-ray satellite and including {\gamma}-ray data from VERITAS, MAGIC, and the Fermi Gamma-ray Space Telescope with the goal of providing a well-sampled multiwavelength baseline measurement of Markarian 501 in the quiescent state. The results of these quiescent-state observations are compared to the historically extreme outburst of April 16, 1997, with the goal of examining variability of the spectral energy distribution between the two states. The derived broadband spectral energy distribution shows the characteristic double-peaked profile. We find that the X-ray peak shifts by over two orders of magnitude in photon energy between the two flux states while the VHE peak varies little. The limited shift in the VHE peak can be explained by the transition to the Klein-Nishina regime. Synchrotron self-Compton models are matched to the data and the implied Klein-Nishina effects are explored., Comment: Accepted for publication in ApJ, 25 pages, 6 figures, corresponding authors: Daniel Gall daniel-d-gall@uiowa.edu and Wei Cui cui@purdue.edu
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- 2010
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43. VERITAS 2008 - 2009 monitoring of the variable gamma-ray source M87
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The VERITAS Collaboration, Acciari, V. A., Aliu, E., Arlen, T., Aune, T., Beilicke, M., Benbow, W., Boltuch, D., Bradbury, S. M., Buckley, J. H., Bugaev, V., Byrum, K., Cannon, A., Cesarini, A., Chow, Y. C., Ciupik, L., Cogan, P., Cui, W., Dickherber, R., Duke, C., Finley, J. P., Finnegan, G., Fortin, P., Fortson, L., Furniss, A., Galante, N., Gall, D., Gillanders, G. H., Godambe, S., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Holder, J., Hui, C. M., Humensky, T. B., Imran, A., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Konopelko, A., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Maier, G., McArthur, S., McCann, A., McCutcheon, M., Millis, J., Moriarty, P., Ong, R. A., Otte, A. N., Pandel, D., Perkins, J. S., Quinn, A. M. J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Rose, H. J., Rovero, A. C., Schroedter, M., Sembroski, G. H., Senturk, G. Demet, Smith, A. W., Steele, D., Swordy, S. P., Theiling, M., Thibadeau, S., Varlotta, A., Vincent, S., Wagner, R. G., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Williams, D. A., Wissel, S., Wood, M., Zitzer, B., Monitoring, Chandra M87, Harris, D. E., and Massaro, F.
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Astrophysics - Cosmology and Nongalactic Astrophysics ,Astrophysics - High Energy Astrophysical Phenomena - Abstract
M87 is a nearby radio galaxy that is detected at energies ranging from radio to VHE gamma-rays. Its proximity and its jet, misaligned from our line-of-sight, enable detailed morphological studies and extensive modeling at radio, optical, and X-ray energies. Flaring activity was observed at all energies, and multi-wavelength correlations would help clarify the origin of the VHE emission. In this paper, we describe a detailed temporal and spectral analysis of the VERITAS VHE gamma-ray observations of M87 in 2008 and 2009. In the 2008 observing season, VERITAS detected an excess with a statistical significance of 7.2 sigma from M87 during a joint multi-wavelength monitoring campaign conducted by three major VHE experiments along with the Chandra X-ray Observatory. In February 2008, VERITAS observed a VHE flare from M87 occurring over a 4-day timespan. The peak nightly flux above 250GeV was 7.7% of the Crab Nebula flux. M87 was marginally detected before this 4-day flare period, and was not detected afterwards. Spectral analysis of the VERITAS observations showed no significant change in the photon index between the flare and pre-flare states. Shortly after the VHE flare seen by VERITAS, the Chandra X-ray Observatory detected the flux from the core of M87 at a historical maximum, while the flux from the nearby knot HST-1 remained quiescent. Acciari et al. (2009) presented the 2008 contemporaneous VHE gamma-ray, Chandra X-ray, and VLBA radio observations which suggest the core as the most likely source of VHE emission, in contrast to the 2005 VHE flare that was simultaneous with an X-ray flare in the HST-1 knot. In 2009, VERITAS continued its monitoring of M87 and marginally detected a 4.2 sigma excess corresponding to a flux of ~1% of the Crab Nebula. No VHE flaring activity was observed in 2009., Comment: 17 pages, 5 figures, accepted for publication in ApJ
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- 2010
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44. Discovery of VHE $\gamma$-ray emission from the SNR G54.1+0.3
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Acciari, V. A., Aliu, E., Arlen, T., Aune, T., Bautista, M., Beilicke, M., Benbow, W., Boltuch, D., Bradbury, S. M., Buckley, J. H., Bugaev, V., Butt, Y., Byrum, K., Cesarini, A., Ciupik, L., Cui, W., Dickherber, R., Duke, C., Finley, J. P., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Gillanders, G. H., Godambe, S., Gotthelf, E. V., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Holder, J., Hui, C. M., Humensky, T. B., Imran, A., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Konopelko, A., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Maier, G., McArthur, S., McCann, A., McCutcheon, M., Moriarty, P., Muhkerjee, R., Ong, R. A., Otte, A. N., Pandel, D., Perkins, J. S., Pohl, M., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Rose, H. J., Schroedter, M., Sembroski, G. H., Senturk, G. Demet, Slane, P., Smith, A. W., Steele, D., Swordy, S. P., Těsić, G., Theiling, M., Thibadeau, S., Vassiliev, V. V., Vincent, S., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Williams, D. A., Wissel, S., Wood, M., and Zitzer, B.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We report the discovery of very high energy gamma-ray emission from the direction of the SNR G54.1+0.3 using the VERITAS ground-based gamma-ray observatory. The TeV signal has an overall significance of 6.8$\sigma$ and appears point-like given the 5$^{arcminute}$ resolution of the instrument. The integral flux above 1 TeV is 2.5% of the Crab Nebula flux and significant emission is measured between 250 GeV and 4 TeV, well described by a power-law energy spectrum dN/dE $\sim$ E$^{-\Gamma}$ with a photon index $\Gamma= 2.39\pm0.23_{stat}\pm0.30_{sys}$. We find no evidence of time variability among observations spanning almost two years. Based on the location, the morphology, the measured spectrum, the lack of variability and a comparison with similar systems previously detected in the TeV band, the most likely counterpart of this new VHE gamma-ray source is the PWN in the SNR G54.1+0.3. The measured X-ray to VHE gamma-ray luminosity ratio is the lowest among all the nebulae supposedly driven by young rotation-powered pulsars, which could indicate a particle-dominated PWN., Comment: 5 pages, 2 figure, Latex, emulateapj style, accepted by the Astrophysical Journal Letters
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- 2010
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45. The Discovery of gamma-Ray Emission From The Blazar RGB J0710+591
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Acciari, V. A., Aliu, E., Arlen, T., Aune, T., Bautista, M., Beilicke, M., Benbow, W., Böttcher, M., Boltuch, D., Bradbury, S. M., Buckley, J. H., Bugaev, V., Byrum, K., Cannon, A., Cesarini, A., Ciupik, L., Cui, W., Dickherber, R., Duke, C., Falcone, A., Finley, J. P., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Gibbs, K., Gillanders, G. H., Godambe, S., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Holder, J., Hui, C. M., Humensky, T. B., Imran, A., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Konopelko, A., Krawczynski, H., Krennrich, F., Lang, M. J., Lamerato, A., LeBohec, S., Maier, G., McArthur, S., McCann, A., McCutcheon, M., Moriarty, P., Mukherjee, R., Ong, R. A., Otte, A. N., Pandel, D., Perkins, J. S., Petry, D., Pichel, A., Pohl, M., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Rose, H. J., Roustazadeh, P., Schroedter, M., Sembroski, G. H., Senturk, G. Demet, Smith, A. W., Steele, D., Swordy, S. P., Tešić, G., Theiling, M., Thibadeau, S., Varlotta, A., Vassiliev, V. V., Vincent, S., Wagner, R. G., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Williams, D. A., Wissel, S., Wood, M., Zitzer, B., Ackermann, M., Ajello, M., Antolini, E., Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Bechtol, K., Bellazzini, R., Berenji, B., Blandford, R. D., Bloom, E. D., Bonamente, E., Borgland, A. W., Bouvier, A., Bregeon, J., Brigida, M., Bruel, P., Buehler, R., Buson, S., Caliandro, G. A., Cameron, R. A., Caraveo, P. A., Carrigan, S., Casandjian, J. M., Cavazzuti, E., Cecchi, C., Çelik, Ö., Charles, E., Chekhtman, A., Cheung, C. C., Chiang, J., Ciprini, S., Claus, R., Cohen-Tanugi, J., Conrad, J., Dermer, C. D., de Palma, F., Silva, E. do Couto e, Drell, P. S., Dubois, R., Dumora, D., Farnier, C., Favuzzi, C., Fegan, S. J., Fortin, P., Frailis, M., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Gehrels, N., Germani, S., Giebels, B., Giglietto, N., Giordano, F., Giroletti, M., Glanzman, T., Godfrey, G., Grenier, I. A., Grove, J. E., Guiriec, S., Hays, E., Horan, D., Hughes, R. E., Jóhannesson, G., Johnson, A. S., Johnson, W. N., Kamae, T., Katagiri, H., Kataoka, J., Knödlseder, J., Kuss, M., Lande, J., Latronico, L., Lee, S. -H., Garde, M. Llena, Longo, F., Loparco, F., Lott, B., Lovellette, M. N., Lubrano, P., Makeev, A., Mazziotta, M. N., Michelson, P. F., Mitthumsiri, W., Mizuno, T., Moiseev, A. A., Monte, C., Monzani, M. E., Morselli, A., Moskalenko, I. V., Murgia, S., Nolan, P. L., Norris, J. P., Nuss, E., Ohno, M., Ohsugi, T., Omodei, N., Orlando, E., Ormes, J. F., Paneque, D., Panetta, J. H., Pelassa, V., Pepe, M., Pesce-Rollins, M., Piron, F., Porter, T. A., Rainò, S., Rando, R., Razzano, M., Reimer, A., Reimer, O., Ripken, J., Rodriguez, A. Y., Roth, M., Sadrozinski, H. F. -W., Sanchez, D., Sander, A., Scargle, J. D., Sgrò, C., Siskind, E. J., Smith, P. D., Spandre, G., Spinelli, P., Strickman, M. S., Suson, D. J., Takahashi, H., Tanaka, T., Thayer, J. B., Thayer, J. G., Thompson, D. J., Tibaldo, L., Torres, D. F., Tosti, G., Tramacere, A., Usher, T. L., Vasileiou, V., Vilchez, N., Vitale, V., Waite, A. P., Wang, P., Winer, B. L., Wood, K. S., Yang, Z., Ylinen, T., and Ziegler, M.
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Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
The high-frequency-peaked BL Lacertae object RGB J0710+591 was observed in the very high-energy (VHE; E > 100 GeV) wave band by the VERITAS array of atmospheric Cherenkov telescopes. The observations, taken between 2008 December and 2009 March and totaling 22.1 hr, yield the discovery of VHE gamma rays from the source. RGB J0710+591 is detected at a statistical significance of 5.5 standard deviations (5.5{\sigma}) above the background, corresponding to an integral flux of (3.9 +/- 0.8) x 10-12 cm-2 s-1 (3% of the Crab Nebula's flux) above 300 GeV. The observed spectrum can be fit by a power law from 0.31 to 4.6 TeV with a photon spectral index of 2.69 +/- 0.26stat +/- 0.20sys. These data are complemented by contemporaneous multiwavelength data from the Fermi Large Area Telescope, the Swift X-ray Telescope, the Swift Ultra-Violet and Optical Telescope, and the Michigan-Dartmouth-MIT observatory. Modeling the broadband spectral energy distribution (SED) with an equilibrium synchrotron self-Compton model yields a good statistical fit to the data. The addition of an external-Compton component to the model does not improve the fit nor brings the system closer to equipartition. The combined Fermi and VERITAS data constrain the properties of the high-energy emission component of the source over 4 orders of magnitude and give measurements of the rising and falling sections of the SED.
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- 2010
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46. Observations of the shell-type SNR Cassiopeia A at TeV energies with VERITAS
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The VERITAS Collaboration, Acciari, V. A., Aliu, E., Arlen, T., Aune, T., Bautista, M., Beilicke, M., Benbow, W., Boltuch, D., Bradbury, S. M., Buckley, J. H., Bugaev, V., Butt, Y., Byrum, K., Cannon, A., Cesarini, A., Chow, Y. C., Ciupik, L., Cogan, P., Cui, W., Dickherber, R., Duke, C., Ergin, T., Fegan, S. J., Finley, J. P., Finnegan, G., Fortin, P., Fortson, L., Furniss, A., Galante, N., Gall, D., Gillanders, G. H., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Holder, J., Huang, D., Hui, C. M., Humensky, T. B., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Konopelko, A., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Maier, G., McArthur, S., McCann, A., McCutcheon, M., Millis, J., Moriarty, P., Ong, R. A., Pandel, D., Perkins, J. S., Pohl, M., Quinn, J., Ragan, K., Reynolds, P. T., Roache, E., Rose, H. J., Schroedter, M., Sembroski, G. H., Smith, A. W., Smith, B. R., Steele, D., Swordy, S. P., Theiling, M., Thibadeau, S., Varlotta, A., Vassiliev, V. V., Vincent, S., Wagner, R. G., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Wissel, S., and Wood, M.
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Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Galaxy Astrophysics - Abstract
We report on observations of very high-energy gamma rays from the shell-type supernova remnant Cassiopeia A with the VERITAS stereoscopic array of four imaging atmospheric Cherenkov telescopes in Arizona. The total exposure time for these observations is 22 hours, accumulated between September and November of 2007. The gamma-ray source associated with the SNR Cassiopeia A was detected above 200 GeV with a statistical significance of 8.3 s.d. The estimated integral flux for this gamma-ray source is about 3% of the Crab-Nebula flux. The photon spectrum is compatible with a power law dN/dE ~ E^(-Gamma) with an index Gamma = 2.61 +/- 0.24(stat) +/- 0.2(sys). The data are consistent with a point-like source. We provide a detailed description of the analysis results, and discuss physical mechanisms that may be responsible for the observed gamma-ray emission., Comment: 27 pages, 2 figures; Accepted for publication in ApJ
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- 2010
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47. Discovery of Variability in the Very High Energy Gamma-Ray Emission of 1ES 1218+304 with VERITAS
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The VERITAS Collaboration, Acciari, V. A., Aliu, E., Beilicke, M., Benbow, W., Boltuch, D., Böttcher, M., Bradbury, S. M., Bugaev, V., Byrum, K., Cesarini, A., Ciupik, L., Cogan, P., Cui, W., Dickherber, R., Duke, C., Falcone, A., Finley, J. P., Finnegan, G., Fortson, L., Furniss, A., Galante, N., Gall, D., Gibbs, K., Guenette, R., Gillanders, G. H., Godambe, S., Grube, J., Hanna, D., Hui, C. M., Humensky, T. B., Imran, A., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Maier, G., McArthur, S., McCann, A., Moriarty, P., Nagai, T., Ong, R. A., Otte, A. N., Pandel, D., Perkins, J. S., Pichel, A., Pohl, M., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Rose, H. J., Schroedter, M., Sembroski, G. H., Smith, A. W., Steele, D., Swordy, S. P., Theiling, M., Thibadeau, S., Vassiliev, V. V., Vincent, S., Wakely, S. P., Weekes, T. C., Weinstein, A., Weisgarber, T., and Williams, D. A.
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Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Cosmology and Extragalactic Astrophysics - Abstract
We present results from an intensive VERITAS monitoring campaign of the high-frequency peaked BL Lac object 1ES 1218+304 in 2008/2009. Although 1ES 1218+304 was detected previously by MAGIC and VERITAS at a persistent level of ~6% of the Crab Nebula flux, the new VERITAS data reveal a prominent flare reaching ~20% of the Crab. While very high energy (VHE) flares are quite common in many nearby blazars, the case of 1ES 1218+304 (redshift z = 0.182) is particularly interesting since it belongs to a group of blazars that exhibit unusually hard VHE spectra considering their redshifts. When correcting the measured spectra for absorption by the extragalactic background light, 1ES 1218+304 and a number of other blazars are found to have differential photon indices less than 1.5. The difficulty in modeling these hard spectral energy distributions in blazar jets has led to a range of theoretical gamma-ray emission scenarios, one of which is strongly constrained by these new VERITAS observations. We consider the implications of the observed light curve of 1ES 1218+304, which shows day scale flux variations, for shock acceleration scenarios in relativistic jets, and in particular for the viability of kiloparsec-scale jet emission scenarios., Comment: 5 pages, 3 figures; Published in The Astrophysical Journal Letters
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- 2010
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48. Highlight Talk: Recent Results from VERITAS
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Ong, R. A., Acciari, V. A., Arlen, T., Aune, T., Beilicke, M., Benbow, W., Boltuch, D., Bradbury, S. M., Buckley, J. H., Bugaev, V., Byrum, K., Cannon, A., Cesarini, A., Ciupik, L., Chow, Y. C., Cogan, P., Cui, W., Duke, C., Fegan, S. J., Finley, J. P., Finnegan, G., Fortin, P., Fortson, L., Furniss, A., Galante, N., Gall, D., Gillanders, G. H., Godambe, S., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Holder, J., Horan, D., Hui, C. M., Humensky, T. B., Imran, A., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Konopelko, A., Krawczynski, H., Krennrich, F., Lang, M. J., Maier, G., McArthur, S., McCann, A., McCutcheon, M., Millis, J., Moriarty, P., Otte, A. N., Pandel, D., Perkins, J. S., Pichel, A., Pohl, M., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Rose, H. J., Schroedter, M., Sembroski, G. H., Smith, A. W., Steele, D., Swordy, S. P., Theiling, M., Thibadeau, S., Toner, J. A., Varlotta, A., Vassiliev, V. V., Vincent, S., Wagner, R. G., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Williams, D. A., Wissel, S., Wood, M., and Zitzer, B.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
VERITAS is a state-of-the-art ground-based gamma-ray observatory that operates in the very high-energy (VHE) region of 100 GeV to 50 TeV. The observatory consists of an array of four 12m-diameter imaging atmospheric Cherenkov telescopes located in southern Arizona, USA. The four-telescope array has been fully operational since September 2007, and over the last two years, VERITAS has been operating with high efficiency and with excellent performance. This talk summarizes the recent results from VERITAS, including the discovery of eight new VHE gamma-ray sources., Comment: Highlight Talk at 31st Int. Cosmic Ray Conference (Lodz 2009). 9 pages and 8 figures. (Fixed rotation of figures)
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- 2009
49. Detection of Extended VHE Gamma Ray Emission from G106.3+2.7 with VERITAS
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VERITAS Collaboration, Acciari, V. A., Aliu, E., Arlen, T., Aune, T., Bautista, M., Beilicke, M., Benbow, W., Boltuch, D., Bradbury, S. M., Buckley, J. H., Bugaev, V., Butt, Y., Byrum, K., Cannon, A., Cesarini, A., Chow, Y. C., Ciupik, L., Cogan, P., Cui, W., Dickherber, R., Ergin, T., Fegan, S. J., Finley, J. P., Fortin, P., Fortson, L., Furniss, A., Gall, D., Gillanders, G. H., Gotthelf, E. V., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Holder, J., Horan, D., Hui, C. M., Humensky, T. B., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Konopelko, A., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Maier, G., McCann, A., McCutcheon, M., Millis, J., Moriarty, P., Mukherjee, R., Ong, R. A., Otte, A. N., Pandel, D., Perkins, J. S., Pohl, M., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Rose, H. J., Schroedter, M., Sembroski, G. H., Smith, A. W., Steele, D., Swordy, S. P., Theiling, M., Toner, J. A., Vassiliev, V. V., Vincent, S., Wagner, R. G., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Williams, D. A., Wissel, S., Wood, M., and Zitzer, B.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We report the detection of very-high-energy (VHE) gamma-ray emission from supernova remnant (SNR) G106.3+2.7. Observations performed in 2008 with the VERITAS atmospheric Cherenkov gamma-ray telescope resolve extended emission overlapping the elongated radio SNR. The 7.3 sigma (pre-trials) detection has a full angular extent of roughly 0.6deg by 0.4deg. Most notably, the centroid of the VHE emission is centered near the peak of the coincident 12CO (J = 1-0) emission, 0.4deg away from the pulsar PSR J2229+6114, situated at the northern end of the SNR. Evidently the current-epoch particles from the pulsar wind nebula are not participating in the gamma-ray production. The VHE energy spectrum measured with VERITAS is well characterized by a power law dN/dE = N_0(E/3 TeV)^{-G} with a differential index of G = 2.29 +/- 0.33stat +/- 0.30sys and a flux of N_0 = (1.15 +/- 0.27stat +/- 0.35sys)x 10^{-13} cm^{-2} s^{-1} TeV^{-1}. The integral flux above 1 TeV corresponds to ~5 percent of the steady Crab Nebula emission above the same energy. We describe the observations and analysis of the object and briefly discuss the implications of the detection in a multiwavelength context., Comment: 5 pages, 2 figures
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- 2009
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50. A connection between star formation activity and cosmic rays in the starburst galaxy M 82
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Acciari, V. A., Aliu, E., Arlen, T., Aune, T., Bautista, M., Beilicke, M., Benbow, W., Boltuch, D., Bradbury, S. M., Buckley, J. H., Bugaev, V., Byrum, K., Cannon, A., Celik, O., Cesarini, A., Chow, Y. C., Ciupik, L., Cogan, P., Colin, P., Cui, W., Dickherber, R., Duke, C., Fegan, S. J., Finley, J. P., Finnegan, G., Fortin, P., Fortson, L., Furniss, A., Galante, N., Gall, D., Gibbs, K., Gillanders, G. H., Godambe, S., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Holder, J., Horan, D., Hui, C. M., Humensky, T. B., Imran, A., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Kildea, J., Konopelko, A., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Maier, G., McArthur, S., McCann, A., McCutcheon, M., Millis, J., Moriarty, P., Mukherjee, R., Nagai, T., Ong, R. A., Otte, A. N., Pandel, D., Perkins, J. S., Pizlo, F., Pohl, M., Quinn, J., Ragan, K., Reyes, L. C., Reynolds, P. T., Roache, E., Rose, H. J., Schroedter, M., Sembroski, G. H., Smith, A. W., Steele, D., Swordy, S. P., Theiling, M., Thibadeau, S., Varlotta, A., Vassiliev, V. V., Vincent, S., Wagner, R. G., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Williams, D. A., Wissel, S., Wood, M., and Zitzer, B.
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Astrophysics - Cosmology and Extragalactic Astrophysics - Abstract
Although Galactic cosmic rays (protons and nuclei) are widely believed to be dominantly accelerated by the winds and supernovae of massive stars, definitive evidence of this origin remains elusive nearly a century after their discovery [1]. The active regions of starburst galaxies have exceptionally high rates of star formation, and their large size, more than 50 times the diameter of similar Galactic regions, uniquely enables reliable calorimetric measurements of their potentially high cosmic-ray density [2]. The cosmic rays produced in the formation, life, and death of their massive stars are expected to eventually produce diffuse gamma-ray emission via their interactions with interstellar gas and radiation. M 82, the prototype small starburst galaxy, is predicted to be the brightest starburst galaxy in gamma rays [3, 4]. Here we report the detection of >700 GeV gamma rays from M 82. From these data we determine a cosmic-ray density of 250 eV cm-3 in the starburst core of M 82, or about 500 times the average Galactic density. This result strongly supports that cosmic-ray acceleration is tied to star formation activity, and that supernovae and massive-star winds are the dominant accelerators., Comment: 18 pages, 4 figures; published in Nature; Version is prior to Nature's in-house style editing (differences are minimal)
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- 2009
- Full Text
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