Discovery of VHEγ-ray emission from the BL Lacertae object B3 2247+381 with the MAGIC telescopes

Aleksić, J.; Alvarez, E. A.; Antonelli, L. A.; Antoranz, P.; Asensio, M.; Backes, M.; Barrio, J. A.; Bastieri, Denis; Becerra González, J.; Bednarek, W.; Berdyugin, A.; Berger, K.; Bernardini, E.; Biland, A.; Blanch, O.; Bock, R. K.; Boller, A.; Bonnoli, G.; Borla Tridon, D.; 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.; De Caneva, G.; De Cea del Pozo, E.; De Lotto, B.; Delgado Mendez, C.; Diago Ortega, A.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, Michele; Elsaesser, D.; Ferenc, D.; Fonseca, M. V.; Font, L.; Fruck, C.; García López, R. J.; 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.; Kellermann, H.; Klepser, S.; Krähenbühl, T.; Krause, J.; La Barbera, A.; Lelas, D.; Leonardo, E.; Lindfors, E.; Lombardi, S.; López, M.; López Oramas, A.; Lorenz, E.; Makariev, M.; Maneva, G.; Mankuzhiyil, N.; Mannheim, K.; Maraschi, L.; Mariotti, Mose'; Martínez, M.; Mazin, D.; Meucci, M.; Miranda, J. M.; Mirzoyan, R.; Miyamoto, H.; Moldón, J.; Moralejo, A.; Munar Adrover, P.; Nieto, D.; Nilsson, K.; Orito, R.; Oya, I.; 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.; Prada Moroni, P. G.; Prandini, Elisa; Puljak, I.; Reichardt, I.; Reinthal, R.; Rhode, W.; Ribó, M.; Rico, J.; Rügamer, S.; Saggion, Antonio; Saito, K.; Saito, T. Y.; Salvati, M.; Satalecka, K.; Scalzotto, VILLI MARIO; Scapin, V.; Arcaro, CORNELIA HANNA ESTHER; Schweizer, T.; Shayduk, M.; Shore, S. N.; Sillanpää, A.; Sitarek, J.; Snidaric, I.; Sobczynska, D.; Spanier, F.; Spiro, S.; Stamatescu, V.; Stamerra, A.; Steinke, B.; Storz, J.; Strah, N.; Surić, T.; Takalo, L.; Takami, H.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Tibolla, O.; Torres, D. F.; Treves, A.; Uellenbeck, M.; Vankov, H.; Vogler, P.; Wagner, R. M.; Weitzel, Q.; Zabalza, V.; Zandanel, F.; Zanin, R.; Kadenius, V.; Weidinger, M.; Buson, S.

doi:10.1051/0004-6361/201117967

Aims. We study the non-thermal jet emission of the BL Lac object B3 2247+381 during a high optical state. Methods. The MAGIC telescopes observed the source during 13 nights between September 30th and October 30th 2010, collecting a total of 14.2 h of good quality very high energy (VHE) gamma-ray data. Simultaneous multiwavelength data was obtained with X-ray observations by the Swift satellite and optical R-band observations at the KVA-telescope. We also use high energy gamma-ray (HE, 0.1-100GeV) data from the Fermi satellite. Results. The BL Lac object B3 2247+381 (z = 0.119) was detected, for the first time, at VHE gamma-rays at a statistical significance of 5.6 sigma. A soft VHE spectrum with a photon index of -3.2 +/- 0.6 was determined. No significant short term flux variations were found. We model the spectral energy distribution using a one-zone SSC-model, which can successfully describe our data.