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Observations of Markarian 421 with the MAGIC telescope

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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 (2007) Observations of Markarian 421 with the MAGIC telescope. Astrophysical journal, 663 (1 (Par). pp. 125-138. ISSN 0004-637X

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Official URL: http://dx.doi.org/10.1086/518221




Abstract

The MAGIC telescope took data of very high energy gamma-ray emission from the blazar Markarian 421 ( Mrk 421) between 2004 November and 2005 April. We present a combined analysis of data samples recorded under different observational conditions, down to gamma- ray energies of 100 GeV. The flux was found to vary between 0.5 and 2 crab ( integrated above 200 GeV), considered a low state when compared to known data. Although the flux varied day by day, no short-term variability was observed, although there is some indication that not all nights show an equally quiescent state. The results at higher energies were found to be consistent with previous observations. A clear correlation is observed between gamma-ray and X-ray fluxes, whereas no significant correlation between gamma-ray and optical data is seen. The spectral energy distribution between 100 GeVand 3 TeV shows a clear deviation from a power law, more clearly and at lower flux than previous observations at higher energies. The deviation persists after correcting for the effect of attenuation by the extragalactic background light, and most likely is source- inherent. There is a rather clear indication of an inverse Compton peak around 100 GeV. The spectral energy distribution of Mrk 421 can be fitted by a one-zone synchrotron self-Compton model, suggesting once again a leptonic origin of the very high energy gamma-ray emission from this blazar.


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© The American Astronomical Society. We would like to thank the IAC for the excellent working conditions at the Observatory de los Muchachos in La Palma. The support of the German BMBF and MPG, the Italian INFN, and the Spanish CICYT is gratefully acknowledged. This work was also supported by ETH research grant TH 34/04 3 and Polish MNiI grant 1P03D01028. We also thank Dieter Horns and Frank Krennrich for providing us with HEGRA, H.E.S.S., and Whipple data.

Uncontrolled Keywords:Extragalactic Background Light, Active Galaxy Markarian-421, TEV Blazar Markarian-421, Spitzer-Space-Telescope, Diffuse Infrared Light, High-Energy Photons, Cobe Dirbe Maps, BL-LAC Objects, 1ST Detections, Gamma-Rays.
Subjects:Sciences > Physics > Electronics
Sciences > Physics > Electricity
Sciences > Physics > Nuclear physics
ID Code:23819
Deposited On:09 Dec 2013 09:25
Last Modified:10 Dec 2018 14:58

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