Fermi gamma-ray space telescope observations of the gamma-ray outburst from 3c454. 3 in november 2010
Abdo, A. A. AA ; Ackermann, M. ; Ajello, M. ; Cavazzuti, E. ; Giommi, P. ;
Jun - 2011
ISSN : 2041-8205 ;
journal : The Astrophysical Journal

Issue : 2
type: Article Journal

Abstract
The flat-spectrum radio quasar 3C454.3 underwent an extraordinary 5 day ³-ray outburst in 2010 November when the daily flux measured with the Fermi Large Area Telescope (LAT) at photon energies E > 100 MeV reached (66 ± 2) × 106 photons cm2 s1. This is a factor of three higher than its previous maximum flux recorded in 2009 December and s 5 times brighter than the Vela pulsar, which is normally the brightest source in the ³-ray sky. The 3 hr peak flux was (85 ± 5)×106 photons cm2 s1, corresponding to an apparent isotropic luminosity of (2.1 ± 0.2)×1050 erg s1, the highest ever recorded for a blazar. In this Letter, we investigate the features of this exceptional event in the ³-ray band of the Fermi-LAT. In contrast to previous flares of the same source observed with the Fermi-LAT, clear spectral changes are observed during the flare.

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