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Fermi LAT detection of gamma-ray flaring activity from the blazar MG J221916+1806 through the Fermi All-sky Variability Analysis (FAVA)

ATel #6020; M. Ajello (Clemson University), D. Kocevski (GSFC/NASA), D. Gasparrini (ASDC/INAF), R. Buehler (DESY/Zeuthen), D. Thompson (GSFC/NASA), S. Ciprini (ASDC/INAF), on behalf of the Fermi Large Area Telescope Collaboration
on 28 Mar 2014; 15:24 UT
Credential Certification: Dario Gasparrini (dario.gasparrini@asdc.asi.it)

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

During the week between March 17 and March 24, 2014, the Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed increased gamma-ray activity from a source positionally coincident with the flat-spectrum radio quasar MG J221916+1806 (also known as 2FGL J2219.1+1805, Nolan et al., 2012, ApJS, 199, 31, and CGRaBS J2219+1806, Healey et al. 2008, ApJ, 175, 97). MG J221916+1806 has radio coordinates RA(J2000)=22h19m14.0925s, DEC(J2000)=+18d06m35.580s (Beasley et al. 2002, ApJS, 141, 13) and has a redshift of z=1.071 (Shaw et al. 2012, ApJ, 748, 49). Preliminary analysis indicates that the source brightened in gamma rays to a flux (E > 100 MeV) of (1.0+/-0.4) x10^-7 ph cm^-2 s^-1 (errors are statistical only). This corresponds to a factor of 20 increase in the source flux with respect to its average flux as reported in the Fermi-LAT 2FGL source catalog.

Because Fermi provides all-sky coverage, regular gamma-ray monitoring of this source will continue. Multiwavelength observations during the ongoing activity of this source are strongly encouraged. The Fermi LAT contact person for MG J221916+1806 is Marco Ajello (e-mail: majello@clemson.edu).

The transient was identified thanks to a new method implemented within the Fermi-LAT Collaboration known as "Fermi All-sky Variability Analysis" that searches the sky for high-energy transients on weekly time scales (Ackermann et al. 2013, ApJ, 771, 57).

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.