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Fermi LAT detection of a rapid and extraordinary GeV outburst from 3C 454.3

ATel #3041; D. Sanchez (dsanchez@llr. in2p3. fr), L. Escande (escande@cenbg. in2p3. fr) on behalf of the Fermi Large Area Telescope Collaboration
on 19 Nov 2010; 00:15 UT
Credential Certification: David J. Thompson (David.J.Thompson@nasa.gov)

Subjects: >GeV, Request for Observations, AGN, Blazar, Quasar, Transient

Referred to by ATel #: 3042, 3043, 3047, 3049, 3055, 3064, 3694, 6236

Following the bright outburst from the FSRQ 3C 454.3 detected by AGILE (ATel #3034), we report time-resolved detail of the detection of this flare by the Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope. Preliminary analysis from 2011-11-16:12:00:00 to 2011-11-17:06:00:00, indicates that the source flux increased by a factor of 4 in 12 hours from a flux of (14 +/- 2)x10-6 photons cm-2 s-1 to (56 +/- 4)x10-6 photons cm-2 s-1 (E>100 MeV, where errors are statistical only). This flux is 2 times higher than the peak reached by the source on 2nd December, 2009 (ATel #2328).

The Preliminary analysis of the 6 hours period from 2011-11-18:06:00:00 to 2011-11-18:12:00:00, indicates the flare is still ongoing with variations of a factor 2 in 3 hours.

The source has undergone a period of high activity and has been detected in high state in different energy bands (see ATels : #2988 (NIR) #3003, #3005 (Optical), #3022 (optical and IR), #3036 (Submillimeter)).

Because Fermi operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. The blazar 3C 454.3 is a "LAT Monitored Source" (http://fermi.gsfc.nasa.gov/FTP/glast/data/lat/catalogs/asp/current/lightcurves/3C454.3_86400.png), and consequently, a quick look estimation of the daily gamma-ray flux observed by Fermi LAT is publicly available (http://fermi.gsfc.nasa.gov/ssc/data/access/). The Fermi LAT contact person are Greg Madejski (madejski@stanford.edu) and Benoit Lott (lott@cenbg.in2p3.fr). Further multiwavelength observations of the source are strongly encouraged

The Fermi LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden.