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Fermi LAT detection of a new gamma-ray flaring source in the vicinity of the the flat spectrum radio quasar NRAO 676 (TXS 2159+505)

ATel #4182; Stefano Ciprini (ASDC and INAF Rome, Italy) and Elizabeth A. Hays (NASA GSFC, USA), on behalf of the Fermi Large Area Telescope Collaboration
on 18 Jun 2012; 12:31 UT
Credential Certification: Stefano Ciprini (stefano.ciprini@asdc.asi.it)

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

Referred to by ATel #: 4189, 4254, 4472, 4486, 4527

The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed gamma-ray flaring activity from a new gamma-ray source not included in any of the Fermi LAT catalogs. Preliminary best-fit location of the gamma-ray source (R.A. = 330.509 deg, Dec. = +50.7581, J2000) has a 95% containment radius of 0.58 deg (statistical errors only) for observations of June 14. This source is positionally consistent with the flat spectrum radio quasar NRAO 676 (also known as TXS 2159+505) placed at R.A.= 330.4314 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 June 16, NRAO 676 was in a high state with an average daily gamma-ray flux (E>100MeV) of (2.3 +/- 0.3) x 10^-6 photons cm^-2 s^-1. (statistical uncertainty only), suggesting an enduring flaring state since the first clear detection occurred on June 14 when the daily gamma-ray flux observed was (2.1 +/- 0.3) x 10^-6 photons cm^-2 s^-1 (statistical uncertainty only).

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.