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New Gamma-ray flaring activity from NRAO 676

ATel #4486; Sara Cutini (INAF-OAR/ASDC) on behalf of Fermi-LAT Collaboration
on 15 Oct 2012; 21:38 UT
Credential Certification: Dario Gasparrini (dario.gasparrini@asdc.asi.it)

Subjects: Gamma Ray, >GeV, AGN, Blazar

Referred to by ATel #: 4527

The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed a renewed gamma-ray flaring activity from a gamma-ray source not included in any of the Fermi LAT catalogs. The source is positionally consistent with the flat spectrum radio quasar NRAO 676 (also known as TXS 2159+505) placed at R.A.= 330.43140 deg, Dec.= 50.81566 deg (J2000, Beasley et al. 2002, ApJS, 141, 13). The redshift of this source is z=1.899 (Sowards-Emmerd et al. 2005, ApJ, 626, 95).

Preliminary analysis indicates that on 2012 October 13, NRAO 676 was in a high state with an daily average gamma-ray flux (E>100MeV) of (2.8 +/- 0.4) x 10^-6 photons cm^-2 s^-1 (statistical uncertainty only).

This flaring activity, which began on October 8 when the daily gamma-ray flux observed was (0.9 +/- 0.3) x 10^-6 photons cm^-2 s^-1 (statistical uncertainty only) appears distinct from the flare in June 2012 (ATel #4182), visible in the public light curve for this source, at http://fermi.gsfc.nasa.gov/FTP/glast/data/lat/catalogs/asp/current/lightcurves/NRAO676_86400.png.

Because Fermi operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. In consideration of the ongoing activity of this source we encourage multiwavelength observations. For this source the Fermi LAT contact persons are S. Ciprini (stefano.ciprini@asdc.asi.it) and E. A. Hays (elizabeth.a.hays@nasa.gov).

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.