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Fermi-LAT detection of a new gamma-ray flare from the NLSy1 PMN J0948+0022

ATel #4694; F. D'Ammando (Univ. Perugia, INFN) and M. Orienti (INAF-IRA Bologna, Univ. Bologna) on behalf of the Fermi Large Area Telescope Collaboration
on 2 Jan 2013; 08:34 UT
Credential Certification: Filippo D'Ammando (filippo.dammando@fisica.unipg.it)

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

Referred to by ATel #: 7266

The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed an increasing gamma-ray flux from a source positionally consistent with PMN J0948+0022 (also known as 2FGL J0948.8+0020, Nolan et al. 2012, ApJS, 199, 31; R.A.= 09h48m57.3201s, Dec.= +00d22'25.558", J2000, Beasley et al. 2002, ApJS, 141, 13), a radio-loud narrow-line Seyfert 1 at z=0.5846 (Sloan Digital Sky Survey, 2004, SDSS2.C).

Preliminary analysis indicates that the source on 2012 December 31 was in a flaring state with a daily gamma-ray flux (E > 100 MeV) of (1.4 +/- 0.4) x10^-6 photons cm^-2 s^-1 (errors are statistical only). On 2013 January 1 the source reached a gamma-ray flux (E > 100 MeV) of (1.7 +/- 0.5) x10^-6 photons cm^-2 s^-1, about 18 times greater than the average flux reported in the second Fermi LAT catalog (Nolan et al. 2012, ApJS, 199, 31). Recently a near-infrared flare from this source was reported in ATel #4659. The Swift/XRT observation performed on 2012 December 30 detected PMN J0948+0022 at the highest count rate in the 0.3-10 keV energy range during the Swift mission (see http://www.swift.psu.edu/monitoring/source.php?source=PMNJ0948+0022 ). Flaring gamma-ray activity from PMN J0948+0022 was previously observed by Fermi-LAT in 2010 July and 2011 June (ATel #2733, ATel #2752, and ATel #3429).

Since Fermi operates in an all-sky scanning mode, regular monitoring of this source will continue. In consideration of the ongoing activity of this source we strongly encourage multiwavelength observations. The Fermi LAT contact persons for this source are Davide Donato (donato@milkyway.gsfc.nasa.gov) and Filippo D'Ammando (filippo.dammando@fisica.unipg.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.