The flat-spectrum radio quasar 3C454.3 underwent an extraordinary 5 day gamma-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) x 10^(-6) photons cm^(-2) s^(-1). This is a factor of three higher than its previous maximum flux recorded in 2009 December and greater than or similar to 5 times brighter than the Vela pulsar, which is normally the brightest source in the gamma-ray sky. The 3 hr peak flux was (85 +/- 5) x 10^(-6) photons cm^(-2) s^(-1), corresponding to an apparent isotropic luminosity of (2.1 +/- 0.2) x10^(50) erg s^(-1), the highest ever recorded for a blazar. In this Letter, we investigate the features of this exceptional event in the gamma-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.
Fermi Gamma-ray Space Telescope Observations of the Gamma-ray Outburst From 3c454.3 In November 2010
BASTIERI, DENIS;BUSON, SARA;RANDO, RICCARDO;TIBALDO, LUIGI;
2011
Abstract
The flat-spectrum radio quasar 3C454.3 underwent an extraordinary 5 day gamma-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) x 10^(-6) photons cm^(-2) s^(-1). This is a factor of three higher than its previous maximum flux recorded in 2009 December and greater than or similar to 5 times brighter than the Vela pulsar, which is normally the brightest source in the gamma-ray sky. The 3 hr peak flux was (85 +/- 5) x 10^(-6) photons cm^(-2) s^(-1), corresponding to an apparent isotropic luminosity of (2.1 +/- 0.2) x10^(50) erg s^(-1), the highest ever recorded for a blazar. In this Letter, we investigate the features of this exceptional event in the gamma-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.Pubblicazioni consigliate
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