Discovery of VHE γ-rays from the blazar 1ES 1215+303 with the MAGIC telescopes and simultaneous multi-wavelength observations
Abstract
Context. We present the discovery of very high energy (VHE, E > 100 GeV) γ-ray emission from the BL Lac object 1ES 1215+303 by the MAGIC telescopes and simultaneous multi-wavelength data in a broad energy range from radio to γ-rays.
Aims: We study the VHE γ-ray emission from 1ES 1215+303 and its relation to the emissions in other wavelengths.
Methods: Triggered by an optical outburst, MAGIC observed the source in 2011 January - February for 20.3 h. The target was monitored in the optical R-band by the KVA telescope that also performed optical polarization measurements. We triggered target of opportunity observations with the Swift satellite and obtained simultaneous and quasi-simultaneous data from the Fermi Large Area Telescope and from the Metsähovi radio telescope. We also present the analysis of older MAGIC data taken in 2010.
Results: The MAGIC observations of 1ES 1215+303 carried out in 2011 January - February resulted in the first detection of the source at VHE with a statistical significance of 9.4σ. Simultaneously, the source was observed in a high optical and X-ray state. In 2010 the source was observed in a lower state in optical, X-ray, and VHE, while the GeV γ-ray flux and the radio flux were comparable in 2010 and 2011. The spectral energy distribution obtained with the 2011 data can be modeled with a simple one zone SSC model, but it requires extreme values for the Doppler factor or the electron energy distribution.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- August 2012
- DOI:
- 10.1051/0004-6361/201219133
- arXiv:
- arXiv:1203.0490
- Bibcode:
- 2012A&A...544A.142A
- Keywords:
-
- BL Lacertae objects: individual: 1ES 1215+303;
- gamma-rays: galaxies;
- Astrophysics - High Energy Astrophysical Phenomena
- E-Print:
- 10 pages, 8 figures, accepted to A&