Paredes i Poy, Josep MariaRibó Gomis, MarcMunar i Adrover, PereMoldón Vara, Francisco Javier2020-02-212020-02-212012-03-020004-6361https://hdl.handle.net/2445/151000Aims: 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) γ-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 γ-ray (HE, 0.1-100 GeV) data from the Fermi satellite. Results: The BL Lac object B3 2247+381 (z = 0.119) was detected, for the first time, at VHE γ-rays at a statistical significance of 5.6σ. 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.application/pdfeng(c) The European Southern Observatory (ESO), 2012Galàxies activesActive galaxiesinfo:eu-repo/semantics/article6128432020-02-21info:eu-repo/semantics/openAccess