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Fermi LAT detection of a new gamma-ray flare from FSRQ PKS 0502+049

ATel #4858; Roopesh Ojha (NASA/GSFC) and Michael Dutka (CUA) on behalf of the Fermi Large Area Telescope Collaboration
on 5 Mar 2013; 02:31 UT
Credential Certification: Roopesh Ojha (Roopesh.Ojha@gmail.com)

Subjects: Gamma Ray, >GeV, AGN, Blazar, Quasar

Referred to by ATel #: 4868, 4870, 4905, 6425, 7279

The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed increasing gamma-ray flux from a source positionally consistent with the flat spectrum radio quasar PKS 0502+049 (also known as 2FGL J0505.5+0501, Nolan et al. 2012 ApJS, 199, 31). PKS 0502+049 has coordinates RA=05h05m23.1847s DEC=+04d59m42.725s, J2000, (Johnston et al. 1995, AJ, 110, 880) and redshift z=0.954 (Drinkwater et al. 1997, MNRAS, 284, 85).

Preliminary analysis indicates that on March 2, 2013 the daily averaged flux (E>100MeV) reached (1.0 +/- 0.2) x 10^-6 ph cm^-2 s^-1 (statistical uncertainty only) which is 34 times its average daily flux from the 2FGL catalog.

It is noteworthy, that further analysis on the flare of August 20, 2011 (ATel#3573) has shown that PKS 0502+049 was the actual counterpart of that flare although the preliminary analysis had identified MG1 J050533+0415 as the possible counterpart.

Because Fermi operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. This source is being added to the "LAT Monitored Sources" and consequently a preliminary estimation of the daily gamma-ray flux observed by Fermi LAT will be publicly available (link:http://fermi.gsfc.nasa.gov/ssc/data/access/lat/msl_lc/). We encourage further multifrequency observations of this source. For this source the Fermi LAT contact person is Roopesh Ojha (Roopesh.Ojha@gmail.com).

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.