Fermi Gamma-ray Space Telescope Observations of the Gamma-ray Outburst from 3C 454.3 in November 2010

TL;DR

This paper reports on a record-breaking gamma-ray outburst from quasar 3C 454.3 observed by Fermi-LAT in November 2010, highlighting unprecedented flux and luminosity levels and spectral changes during the event.

Contribution

It presents detailed observations of an extraordinary gamma-ray flare from 3C 454.3, including the highest flux and luminosity ever recorded for a blazar, with analysis of spectral variations.

Findings

Record gamma-ray flux and luminosity during the flare.

Spectral changes observed during the event.

Comparison with previous flares shows unique features.

Abstract

The flat-spectrum radio quasar 3C 454.3 underwent an extraordinary 5-day gamma-ray outburst in November 2010 where the daily flux measured with the Fermi Large Area Telescope (LAT) at photon energies E>100 MeV reached (66+/-2) x 10^-6 ph cm^-2 s^-1. This is a factor of 3 higher than its previous maximum flux recorded in December 2009 and ~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 ph cm^-2 s^-1, corresponding to an apparent isotropic luminosity of 2.1+/-0.2 10^50 erg s^-1, the highest ever recorded for a blazar. In this paper, 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.