AGILE detection of a strong gamma-ray flare from the blazar 3C 454.3

Abstract

We report the first blazar detection by the AGILE satellite. AGILE detected 3C 454.3 during a period of strongly enhanced optical emission in July 2007. AGILE observed the source with a dedicated repointing during the period 2007 July 24-30 with its two co-aligned imagers, the Gamma-Ray Imaging Detector and the hard X-ray imager Super-AGILE sensitive in the 30 MeV-50 GeV and 18-60 keV, respectively. Over the entire period, AGILE detected gamma-ray emission from 3C 454.3 at a significance level of 13.8-$\sigma$ with an average flux (E$>$100 MeV) of $(280\pm 40)\times 10^{-8}$ photons cm${}^{-2}$ s${}^{-1}$. The gamma-ray flux appears to be variable towards the end of the observation. No emission was detected by Super-AGILE in the energy range 20-60 keV, with a 3-$\sigma$ upper limit of $2.3\times 10^{-3}$ photons cm${}^{-2}$ s${}^{-1}$. The gamma-ray flux level of 3C 454.3 detected by AGILE is the highest ever detected for this quasar and among the most intense gamma-ray fluxes ever detected from Flat Spectrum Radio Quasars.

Accepted by Astrophysical Journal Letters; 14 pages, 3 EPS Figures, 1 Table

References in corpus (4)

• Sub-milliarcsecond Imaging of Quasars and Active Galactic Nuclei III. Kinematics of Parsec-Scale Radio Jets
• SuperAGILE: the hard X-ray Imager for the AGILE space mission
• Swift and infra-red observations of the blazar 3C~454.3 during the giant X-ray flare of May 2005
• INTEGRAL observations of the blazar 3C454.3 in outburst

Cited by in corpus (11)

• A new activity phase of the blazar 3C 454.3. Multifrequency observations by the WEBT and XMM-Newton in 2007-2008
• Multiwavelength observations of 3C 454.3. I. The AGILE 2007 November campaign on the "Crazy Diamond"
• The Supernova Remnant W44: confirmations and challenges for cosmic-ray acceleration
• The high activity of 3C 454.3 in autumn 2007. Monitoring by the WEBT during the AGILE detection
• The Second AGILE Catalog of Gamma-Ray Sources
• Long-term optical spectroscopic variations in blazar 3C 454.3
• MAGIC upper limits to the VHE gamma-ray flux of 3C454.3 in high emission state
• Spectral index-mass accretion rate correlation and evaluation of black hole masses in AGNs 3C~454.3 and M87
• Modeling the spectral-energy-distribution of 3C 454.3 in a "flat" broad-line-region scenario
• Revisiting radio variability of the blazar 3C 454.3
• The origin of Cosmic-Rays from SNRs: confirmations and challenges after the first direct proof