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Fermi LAT detection of a GeV flare from PKS 0235-618

ATel #2669; Sara Cutini (ASI-Science Data Center) on behalf of the Fermi Large Area Telescope Collaboration
on 11 Jun 2010; 18:57 UT
Distributed as an Instant Email Notice Request For Observations
Credential Certification: Dario Gasparrini (dario.gasparrini@asdc.asi.it)

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

Referred to by ATel #: 2673

The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed an increasing gamma-ray flux from 1FGL J0238.3-6132 (Abdo, A. et al 2010, ApJ, 715, 429) a source positionally consistent with the Flat Spectrum Radio Quasar PKS 0235-618 (RA: 02h36m53.2457s DEC: -61d36m15.183, J2000, Fey, A. et al. 2004, AJ, 127, 1791) with a redshift of z=0.465 (Healey, S. et al. 2008, ApJS, 175, 97).

Preliminary analysis indicates that the source was detected on 2010-06-10 for the first time in the daily time scale with a gamma-ray flux (E>100MeV) of (1.11+/-0.30)E-6 ph/cm^2/s (statistical uncertainty only) more than 40 times the flux reported in the 1FGL catalogue. It reached a gamma-ray flux (E>100MeV) of (2.26 +/-1.20)E-6 ph/cm^2/s measured over six hours starting at 00:00:00 2010-06-10 UTC. 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 strongly encourage multiwavelength observations. For this source the Fermi LAT contact person Sara Cutini (sara.cutini@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.