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Fermi LAT detection of GeV flare from blazar PKS 2023-07

ATel #2175; D. Gasparrini (ASDC) on behalf of the Fermi Large Area Telescope Collaboration
on 27 Aug 2009; 13:38 UT
Distributed as an Instant Email Notice Request For Observations
Credential Certification: Dario Gasparrini (dario.gasparrini@asdc.asi.it)

Subjects: Gamma Ray, >GeV, AGN, Quasar

Referred to by ATel #: 2179, 8879, 8932

The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, detected on August 23, 2009 increasing gamma-ray activity from a source positionally consistent with the EGRET flat spectrum radio quasar PKS 2023-07 also known as 3EG J2025-0744, 0FGL J2025.6-0736 (RA: 160h 25m 40.6604s -07d 35m 52.688s, J2000.0, ref. Beasley, A. J. et l 2002, ApJS, 141, 13B; redshift 1.388, ref. Drinkwater, M. J. et al. 1997, MNRAS, 284, 85D).

Preliminary analysis indicates that on August 23, 2009, PKS 2023-07 appeared in a high state with a gamma-ray flux (E>100MeV) of 1.42+/-0.28 x 10^-6 photons cm^-2 s^-1 (statistical only), which represents an increase of a factor of 3 with respect to the source flux level indicated in Abdo et al. 2009, ApJ, 700, 597A.

Because Fermi operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue. In consideration of the ongoing gamma-ray activity, we strongly encourage multiwavelength observations. For the source the Fermi LAT contact person is D. Bastieri (bastieri@pd.infn.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.