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

J Aleksić,V Scalzotto,J A Barrio,A La Barbera,J Becerra González,E De Cea Del Pozo,D Dominis Prester,T Bretz,S Buson,J Pochon,L Font,L Peruzzo,S Rügamer,T Schweizer,A De Angelis,E Lorenz,P Antoranz,M Doro,T Krähenbühl,J Cortina,A Boller,E Prandini,D Hildebrand,J Hose,N Strah,W Bednarek,A Stamerra,C Delgado Mendez,J M Paredes,D Höhne-Mönch,L Cossio,D Bastieri,E Carmona,Q Weitzel,M Mariotti,M Shayduk,T Jogler,G Giavitto,M V Fonseca,V Scapin,V Zabalza,M Pasanen,D Tescaro,M Garczarczyk,E Leonardo,R Reinthal,P G Prada Moroni,K Satalecka,A Berdyugin,D Mazin,M Pilia,H Takami,E Colombo,N Mankuzhiyil,D Nieto,A Carosi,V Kadenius,H Vankov,P Colin,R Orito,R Mirzoyan,W Rhode,S Partini,B De Lotto,A López-Oramas,D Paneque,J Storz,D Hadasch,A Diago Ortega,J Krause,D Borla Tridon,A Sillanpää,A Cañellas,M Uellenbeck,A Domínguez,B Steinke,J Moldón,M Doert,G De Caneva,O Tibolla,L Maraschi,M Salvati,A Herrero,S Klepser,A Saggion,G Maneva,M Asensio,K Berger,R J García López,H Kellermann,P Munar-Adrover,J Rico,S Spiro,Bernhard A Huber ,C Fruck,L A Antonelli,K Mannheim,R Böck ,F Tavecchio,Daniel Garrido ,M Peršić ,A Biland,F Dazzi,I Reichardt,L O Takalo ,I Braun,M Teshima,S Lombardi,D Dorner,M Weidinger,J Sitarek,D Sobczyńska ,I Puljak,E Bernardini,P Vogler,Michael Backes ,E Lindfors,C Schultz,S Covino,Koji Saito ,F Zandanel,R Paoletti,T Surić,Sharon Pardo ,D Lelas,V Stamatescu,H Miyamoto,M Meucci,G Bonnoli,R M Wagner,Dario Hrupec ,D F Torres,F Pauß ,M A Pérez-Torres ,Steven N Shore ,M Ribó,O Blanch,A Moralejo,J M Miranda,K Nilsson,D Häfner,R Zanin,P Temnikov,F Spanier,Iva Šnidarić ,M Martı́nez ,D Elsäesser ,M López,D Ferenc,T Terzić,I Oya,N Godinović,Francisco Prada ,Takayuki Saito ,A Treves,M Makariev,Ezequiel Álvarez ,J L Contreras

doi:10.1051/0004-6361/201117967

Abstract

We study the non-thermal jet emission of the BL Lac object B3 2247+381 during a high optical state. The MAGIC telescopes observed the source during 13 nights between September 30th and October 30th 2010, collecting a total of 14.2 hours 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 GeV-100 GeV) data from the Fermi satellite. 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 $\pm$ 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.

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