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PKS 1329-049 revived: new gamma-ray activity observed by Fermi LAT

ATel #2837; K. V. Sokolovsky (MPIfR/ASC Lebedev) and F. K. Schinzel (MPIfR); on behalf of the Fermi Large Area Telescope Collaboration
on 9 Sep 2010; 09:28 UT
Distributed as an Instant Email Notice Request For Observations
Credential Certification: Frank Schinzel (schinzel@mpifr-bonn.mpg.de)

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

The Large Area Telescope (LAT), one of the two instruments aboard the Fermi Gamma-ray Space Telescope, has observed a sharply increasing gamma-ray flux from a source positionally consistent with the high-redshift blazar PKS 1329-049 (1FGL J1331.9-0506, Abdo et al. 2010, ApJS, 188, 405; z = 2.15, Thompson et al. 1990, PASP, 102, 1235).

Preliminary analysis indicates that the source on September 06, 2010, was in a high state with a gamma-ray flux (E>100MeV) of (3.0 +/-0.5) x10^-6 photons cm^-2 s^-1 (all errors are statistical only), making it the brightest source in the extragalactic gamma-ray sky on that day. On September 07, the source was still bright with a flux of (2.3 +/-0.7) x10^-6 photons cm^-2 s^-1. Previously, the source was detected by Fermi on the 1-day timescale on September 22, 2009, and July 07, 2010, at a flux level of about 1.0 x10^-6 photons cm^-2 s^-1 (ATel #2728).

Because Fermi operates in an all-sky scanning mode, regular gamma-ray monitoring of PKS 1329-049 will continue. The source is currently only 37 degrees away from the Sun which makes multiwavelength observations challenging, however we strongly encourage follow-up in other bands if possible. The Fermi LAT contact person for this source is D. Donato (donato@milkyway.gsfc.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.