ar X iv : a st ro - p h / 06 06 16 1 v 1 7 J un 2 00 6 Detection of VHE radiation from the BL Lac PG 1553 + 113 with the MAGIC telescope

Abstract

The MAGIC telescope has observed very high energy gamma-ray emission from the distant BL Lac object PG 1553+113 in 2005 and 2006. The overall significance is 8.8 σ in 18.8 h. The light curve shows no significant flux variations on a daily time-scale, the flux level during 2005 was, however, significantly higher compared to 2006. The differential energy spectrum between ∼ 90 GeV and 500 GeV is well described by a power law with spectral index 4.2 ± 0.3. The Universität Würzburg, D-97074 Würzburg, Germany Institut de F́ısica d’Altes Energies, E-08193 Bellaterra (Barcelona), Spain ETH Zurich, CH-8093 Switzerland Universidad Complutense, E-28040 Madrid, Spain Universitat Autònoma de Barcelona, E-08193 Bellaterra, Spain Universität Dortmund, D-44227 Dortmund, Germany Max-Planck-Institut für Physik, D-80805 München, Germany Università di Padova and INFN, I-35131 Padova, Italy Università di Udine, and INFN Trieste, I-33100 Udine, Italy University of Lódź, PL-90236 Lodz, Poland Yerevan Physics Institute, AM-375036 Yerevan, Armenia Tuorla Observatory, FI-21500 Piikkiö, Finland Humboldt-Universität zu Berlin, D-12489 Berlin, Germany University of California, Davis, CA-95616-8677, USA Università di Siena, and INFN Pisa, I-53100 Siena, Italy Università di Trieste, and INFN Trieste, I-34100 Trieste, Italy Institute for Nuclear Research and Nuclear Energy, BG-1784 Sofia, Bulgaria INAF/Osservatorio Astronomico and INFN Trieste, I-34131 Trieste, Italy Università di Pisa, and INFN Pisa, I-56126 Pisa, Italy Institut de Ciències de l’Espai, E-08193 Bellaterra (Barcelona), Spain Universitat de Barcelona, E-08028 Barcelona, Spain deceased correspondence: D. Kranich: kranich@physics.ucdavis.edu

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@inproceedings{Hakobyan2006arXI, title={ar X iv : a st ro - p h / 06 06 16 1 v 1 7 J un 2 00 6 Detection of VHE radiation from the BL Lac PG 1553 + 113 with the MAGIC telescope}, author={Davit Hakobyan and Masaaki Hayashida and Erno Lindfors and Stephen Lombardi and Priyadarshi Majumdar and Riccardo Paoletti and Josep M. Paredes and Mikko Pasanen and Donatella Pascoli and Felicitas Pauss}, year={2006} }