The extraordinary gamma-ray flare of the blazar 3C 454.3

TL;DR

This paper reports on a record-breaking gamma-ray flare from blazar 3C 454.3 in December 2009, highlighting its unprecedented brightness, energy output, and spectral evolution, with significant implications for understanding blazar physics.

Contribution

The study presents detailed gamma-ray observations of an extraordinary flare from 3C 454.3, providing new insights into its intensity, spectral changes, and energy release, which were not previously documented.

Findings

Peak gamma-ray flux of (2000 ± 400) x 10^-8 ph cm^-2 s^-1

Total energy emitted during the flare approximately 10^56 erg

Gamma-ray luminosity reached about 3 x 10^46 erg s^-1

Abstract

We present the gamma-ray data of the extraordinary flaring activity above 100 MeV from the flat spectrum radio quasar 3C 454.3 detected by AGILE during the month of December 2009. 3C 454.3, that has been among the most active blazars of the FSRQ type since 2007, was detected in the gamma-ray range with a progressively rising flux since November 10, 2009. The gamma-ray flux reached a value comparable with that of the Vela pulsar on December 2, 2009. Remarkably, between December 2 and 3, 2009 the source more than doubled its gamma-ray emission and became the brightest gamma-ray source in the sky with a peak flux of F_{\gamma,p} = (2000 \pm 400) x 10^-8 ph cm^-2 s^-1 for a 1-day integration above 100 MeV. The gamma-ray intensity decreased in the following days with the source flux remaining at large values near F \simeq (1000 \pm 200) x 10^-8 ph cm^-2 s^-1 for more than a week. This exceptional gamma-ray flare dissipated among the largest ever detected intrinsic radiated power in gamma-rays above 100 MeV (L_{\gamma, source, peak} \simeq 3 x 10^46 erg s^-1, for a relativistic Doppler factor of {\delta} \simeq 30). The total isotropic irradiated energy of the month-long episode in the range 100 MeV - 3 GeV is E_{\gamma,iso} \simeq 10^56 erg. We report the intensity and spectral evolution of the gamma-ray emission across the flaring episode. We briefly discuss the important theoretical implications of our detection.