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Fermi-LAT detection of a GeV gamma-ray flare from blazar PKS 0336-01 (CTA 26)

ATel #6568; Stefano Ciprini (ASI Science Data Center and INAF Observatory of Rome, Italy), on behalf of the Fermi Large Area Telescope Collaboration.
on 12 Oct 2014; 19:29 UT
Credential Certification: Stefano Ciprini (stefano.ciprini@asdc.asi.it)

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

Referred to by ATel #: 6577, 6662, 10185

The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed increasing gamma-ray flux from a source positionally consistent with the flat spectrum radio quasar PKS 0336-01 (also known as CTA 26, DA 110, S3 0336-01) with radio coordinates, (J2000.0), R.A.: 54.87891 deg, Dec: -1.77661 deg (Johnston et al. 1995, AJ, 110, 880 ). This blazar has a redshift of 0.852 (Hewitt & Burbidge 1989).

Preliminary analysis indicates that PKS 0336-01 (CTA 26) on October 11, 2014, was in a high state with a daily averaged gamma-ray flux (E>100MeV) of (1.1+/-0.3)X 10^-6 photons cm^-2 s^-1 (statistical uncertainty only), about 20 times greater than the average flux reported in the second Fermi-LAT catalog (2FGL J0339.4-0144 , Nolan et al. 2012, ApJS, 199, 31). PKS 0336-01 (CTA 26) was also observed to be in an active gamma-ray state by the LAT near the end of 2010 and the beginning of 2011, but this is the first time that such a high level of GeV emission is detected on daily time scales since the outburst observed by EGRET in 1995 (Mattox et al. 2001, ApJ, 549, 906). The source is not reported in the 1AGL catalog of AGILE.

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 Roopesh Ojha (Roopesh.Ojha@gmail.com) and Stefano Ciprini (stefano.ciprini@asdc.asi.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.