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MAGIC observations of the giant radio galaxy M 87 in a low-emission state between 2005 and 2007

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Antoranz Canales, Pedro and Barrio Uña, Juan Abel and Contreras González, José Luis and Fonseca González, Mª Victoria and López Moya, Marcos and Miranda Pantoja, José Miguel and Nieto, Daniel and Satalecka, Konstanzja and Scapin, Valeria (2012) MAGIC observations of the giant radio galaxy M 87 in a low-emission state between 2005 and 2007. Astronomy & Astrophysics, 544 . ISSN 0004-6361

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Official URL: http://dx.doi.org/10.1051/0004-6361/201117827




Abstract

Context. We present the results of a long M 87 monitoring campaign in very high energy.-rays with the MAGIC-I Cherenkov telescope. Aims. We aim to model the persistent non-thermal jet emission by monitoring and characterizing the very high energy gamma-ray emission of M 87 during a low state. Methods. A total of 150 h of data were taken between 2005 and 2007 with the single MAGIC-I telescope, out of which 128.6 h survived the data quality selection. We also collected data in the X-ray and Fermi-LAT bands from the literature (partially contemporaneous). Results. No flaring activity was found during the campaign. The source was found to be in a persistent low-emission state, which was at a confidence level of 7 sigma. We present the spectrum between 100 GeV and 2 TeV, which is consistent with a simple power law with a photon index Gamma = 2.21 +/- 0.21 and a flux normalization at 300GeV of (7.7 +/- 1.3) x 10(-8) TeV-1 s(-1) m(-2). The extrapolation of the MAGIC spectrum into the GeV energy range matches the previously published Fermi-LAT spectrum well, covering a combined energy range of four orders of magnitude with the same spectral index. We model the broad band energy spectrum with a spine layer model, which can satisfactorily describe our data.


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© ESO 2012. We would like to thank the Instituto de Astrofísica de Canarias for the excellent working conditions at the Observatorio del Roque de los Muchachos in La Palma. The support of the German BMBF and MPG, the Italian INFN, the Swiss National Fund SNF, and the Spanish MICINN is gratefully acknowledged. This work was also supported by the CPAN CSD2007-00042 and MultiDark CSD2009-00064 projects of the Spanish Consolider-Ingenio 2010 programme, by grant DO02-353 of the Bulgarian NSF, by grant 127740 of the Academy of Finland, by the DFG Cluster of Excellence “Origin and Structure of the Universe”, by the DFG Collaborative Research Centers SFB823/C4 and SFB876/C3, and by the Polish MNiSzW grant 745/N-HESSMAGIC/2010/0.

Uncontrolled Keywords:Gamma-Ray Emission, Atmospheric Cherenkov Telescope, Fast TEV Variability, M87 Jet, Black-Hole, Unified Schemes, Crab-Nebula, Energy, Blazars, Performance.
Subjects:Sciences > Physics > Electricity
Sciences > Physics > Electronics
Sciences > Physics > Nuclear physics
ID Code:24860
Deposited On:01 Apr 2014 09:21
Last Modified:10 Dec 2018 14:58

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