OBSERVATIONS OF THE BLAZAR 3C 66A WITH THE MAGIC TELESCOPES IN STEREOSCOPIC MODE

/ Authors

T. M. C. J. Aleksi'c, L. A. Antonelli, P. Antoranz, Michael Backes, J. Barrio, D. Bastieri, J. Gonz'alez, W. Bednarek, A. Berdyugin, K. Berger

and 218 more authors

E. Bernardini, A. Biland, O. Blanch, R. Bock, A. Boller, G. Bonnoli, P. Bordas, D. Tridon, V. Bosch-Ramon, D. Bose, I. Braun, T. Bretz, M. Cámara, A. Cañellas, E. Carmona, A. Carosi, P. Colin, E. Colombo, J. Contreras, J. Cortina, L. Cossio, S. Covino, F. Dazzi, A. Angelis, E. C. D. Pozo, B. Lotto, M. D. Maria, F. D. Sabata, C. Mendez, A. Ortega, M. Doert, A. Domínguez, D. Prester, D. Dorner, M. Doro, D. Elsaesser, M. Errando, D. Ferenc, M. Fonseca, L. Font, R. L'opez, M. Garczarczyk, D. Garrido, G. Giavitto, N. Godinovi'c, D. Hadasch, A. Herrero, D. Hildebrand, D. Hohne-Monch, J. Hose, D. Hrupec, B. Huber, T. Jogler, S. Klepser, T. Krahenbuhl, D. Kranich, J. Krause, A. Barbera, D. Lelas, E. Leonardo, E. Lindfors, S. Lombardi, F. Longo, M. L'opez, E. Lorenz, P. Majumdar, M. Makariev, G. Maneva, N. Mankuzhiyil, K. Mannheim, L. Maraschi, M. Mariotti, M. Mart'inez, D. Mazin, M. Meucci, J. Miranda, R. Mirzoyan, H. Miyamoto, J. Mold'on, A. Moralejo, D. Nieto, K. Nilsson, R. Orito, I. Oya, R. Paoletti, S. Pardo, J. Paredes, S. Partini, M. Pasanen, F. Pauss, R. Pegna, M. Pérez-Torres, M. Persic, L. Peruzzo, J. Pochon, F. Prada, P. Moroni, E. Prandini, N. Puchades, I. Puljak, I. Reichardt, R. Reinthal, W. Rhode, M. Rib'o, J. Rico, S. Rugamer, A. Saggion, K. Saito, T. Saito, M. Salvati, M. S'anchez-Conde, K. Satalecka, V. Scalzotto, V. Scapin, C. Schultz, T. Schweizer, M. Shayduk, S. Shore, A. Sierpowska-Bartosik, A. Sillanpaa, J. Sitarek, D. Sobczynska, F. Spanier, S. Spiro, A. Stamerra, B. Steinke, J. Storz, N. Strah, J. Struebig, T. Suri'c, L. Takalo, F. Tavecchio, P. Temnikov, T. Terzi'c, D. Tescaro, M. Teshima, M. Thom, D. Torres, H. Vankov, P. Vogler, R. Wagner, Q. Weitzel, V. Zabalza, F. Zandanel, R. Z. Ifae, Edifici Cn., Campus Uab, E-08193 Bellaterra, Spain., I. I. F. Astrophysics, I-00136 Rome, Italy., U. Siena, I. Pisa, I-53100 Siena, Technische Universitat Dortmund, D. Dortmund, H Germany, U. Complutense, E. Madrid, U. Padova, Infn, I-35131 Padova, Instituto de Astrof'isica de Canarias, E. Laguna, Tenerife, D. Astrof'isica, U. L. Laguna, E. Laguna, University of L'od'z, PL-90236 Lodz, Poland, T. Observatory, U. Turku, FI-21500 Piikkio, Finland., D. Elektronen-Synchrotron, D. Zeuthen, E. Zurich, CH-8093 Switzerland, M. F. Physik, D-80805 Munchen, U. Barcelona, E. Barcelona, U. Wurzburg, D-97074 Wurzburg, U. Udine, I. Trieste, I. Udine, Institut de Ci'encies de l'Espai, Inst. de Astrof'isica de Andaluc'ia, E-18080 Granada, Croatian Magic Consortium, I. R. Bošković, University of Rijeka, University of Split, HR-10000 Zagreb, Croatia., U. Barcelona, Inst. for Nucl. Research, Nucl. Energy, BG-1784 Sofia, Bulgaria., INAF-Osservatorio Astronomico, I. Trieste, Icrea, E. Barcelona, U. Pisa, I. Pisa, N. C. E. P. F. D. Lausanne, Lausanne, Switzerland., supported by Infn Padova, N. A. C. D. I. Energ'eticas, Medioambientales y Tecnol'ogicas, Madrid, N. Eso, Turku

/ Abstract

We report new observations of the intermediate-frequency peaked BL Lacertae object 3C 66A with the MAGIC telescopes. The data sample we use were taken in 2009 December and 2010 January, and comprises 2.3 hr of good quality data in stereoscopic mode. In this period, we find a significant signal from the direction of the blazar 3C 66A. The new MAGIC stereoscopic system is shown to play an essential role for the separation between 3C 66A and the nearby radio galaxy 3C 66B, which is at a distance of only 6′. The derived integral flux above 100 GeV is 8.3% of the Crab Nebula flux and the energy spectrum is reproduced by a power law of photon index 3.64 ± 0.39stat ± 0.25sys. Within errors, this is compatible with the one derived by VERITAS in 2009. From the spectra corrected for absorption by the extragalactic background light, we only find small differences between the four models that we applied, and constrain the redshift of the blazar to z < 0.68.

Journal: The Astrophysical Journal

DOI: 10.1088/0004-637X/726/2/58