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Title: | Very high energy gamma-ray observations of strong flaring activity in M87 in 2008 February |
Author: | MAGIC Collaboration Bosch i Ramon, Valentí Ribó Gomis, Marc Paredes i Poy, Josep Maria |
Keywords: | Raigs gamma Galàxies Gamma rays Galaxies |
Issue Date: | 22-Aug-2008 |
Publisher: | Institute of Physics (IOP) |
Abstract: | M87 is the only known nonblazar radio galaxy to emit very high energy (VHE) gamma rays. During a monitoring program of M87, a rapid flare in VHE gamma-rays was detected by the MAGIC telescope in early 2008. The flux was found to be variable above 350 GeV on a timescale as short as 1 day at a significance level of 5.6 σ. The highest measured flux reached 15% of the Crab Nebula flux. We observed several substantial changes of the flux level during the 13 day observing period. The flux at lower energies (150-350 GeV), instead, is compatible with being constant. The energy spectrum can be described by a power law with a photon index of 2.30 ± 0.11stat ± 0.20syst. The observed day-scale flux variability at VHE prefers the M87 core as source of the emission and implies that either the emission region is very compact (just a few Schwarzschild radii) or the Doppler factor of the emitting blob is rather large in the case of a nonexpanding emission region. |
Note: | Reproducció del document publicat a: https://doi.org/10.1086/592348 |
It is part of: | Astrophysical Journal Letters, 2008, vol. 685, num. 1, p. 23-26 |
URI: | http://hdl.handle.net/2445/150143 |
Related resource: | https://doi.org/10.1086/592348 |
ISSN: | 2041-8205 |
Appears in Collections: | Articles publicats en revistes (Física Quàntica i Astrofísica) |
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