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Fermi-LAT detection of a gamma-ray flare from the likely AGN PMN J1123-6417

ATel #3394; F. D'Ammando (INAF-IASF Palermo and CIFS) on behalf of the Fermi Large Area Telescope Collaboration
on 1 Jun 2011; 16:52 UT
Credential Certification: Filippo D'Ammando (filippo.dammando@iasf-roma.inaf.it)

Subjects: Gamma Ray, >GeV, Request for Observations, AGN, Blazar

The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed increased gamma-ray activity from the Fermi source 1FGL J1122.9-6415 (Abdo et al. 2010, ApJS, 188, 405).

1FGL J1122.9-6415 is associated to PMN J1123-6417 (R.A.= 11:23:19.48, Dec.=-64:17:35.7, J2000.0; Mahony et al. 2010, ApJ, 718, 587), a likely AGN of uncertain type at a Galactic latitude, b=-3 deg. This association is confirmed also by Mahony et al. (2010) using the AT20G survey catalog. No redshift is known for this object. This source is present also in the Fermi-LAT Bright Source List, based on the first three months of operation, as 0FGL J1123.0-6416 (Abdo et al. 2009, ApJ, 700, 597).

Preliminary analysis indicates that PMN J1123-6417 on May 30, 2011 was in a high state, with a daily gamma-ray flux (E > 100 MeV) of (1.4 +/- 0.4) x 10^-6 ph cm^-2 s^-1 (statistical uncertainty only), which represents an increase of a factor of 25 with respect to the average source flux observed in the first eleven months of Fermi observations (Abdo et al. 2010, ApJS, 188, 405).

Because Fermi operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. In consideration of the activity of this source we strongly encourage multiwavelength observations. The Fermi LAT contact person for this source is F. D'Ammando (dammando@ifc.inaf.it).

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.