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Fermi LAT Detection of a New Gamma-ray Source Associated with B2 0748+33

ATel #9590; C. C. Cheung (NRL), on behalf of the Fermi Large Area Telescope Collaboration
on 3 Oct 2016; 22:35 UT
Credential Certification: Teddy Cheung (ccheung@milkyway.gsfc.nasa.gov)

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

Referred to by ATel #: 9627, 9752

The Large Area Telescope (LAT), one of two instruments on the Fermi Gamma-ray Space Telescope, has observed strong gamma-ray emission from a source positionally consistent with the flat-spectrum radio quasar B2 0748+33 with coordinates R.A. = 117.9736383 deg, Decl. = 33.2221719 deg (J2000; Petrov & Taylor 2011 AJ 142, 89) at redshift, z=1.936 (Hewett & Wild 2010 MNRAS 405, 2302). This source is not in any published LAT catalog and was not detected by AGILE or EGRET.

Preliminary analysis indicates that the source was detected in gamma rays on 2016 Oct 2 with a daily-averaged flux (E > 100 MeV) of (0.8+/-0.2) x10^-6 ph cm^-2 s^-1 with a single power-law photon index of 2.1+/-0.2 (errors are statistical only).

The source was also detected in the week beginning 2016 Sep 19 by the 'Fermi All-sky Variability Analysis' (FAVA) that searches the entire sky for high-energy transients on weekly time scales; see: http://fermi.gsfc.nasa.gov/ssc/data/access/lat/FAVA/ .

Because Fermi operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue and its light curve will be available at the Fermi Science Support Center page (see http://fermi.gsfc.nasa.gov/ssc/data/access/lat/msl_lc/ ). In consideration of the activity of this source we encourage multiwavelength observations. For this source the Fermi LAT contact person is C. C. Cheung (Teddy.Cheung at nrl.navy.mil).

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.