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Fermi LAT detection of a GeV flare from PKS 0426-380

ATEL # 2366; Y. T. Tanaka (ISAS/JAXA) on behalf of the Fermi Large Area Telescope Collaboration
on 4 Jan 2010; 7:09 UT
Password Certification: Yasuyuki T. Tanaka (tanaka@astro.isas.jaxa.jp)

Subjects: Gamma Ray, >GeV, Transients

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 a source positionally consistent with the "BL Lac" object PKS 0426-380 (RA: 04h28m40.4242s, Dec: -37d56m19.579s, J2000; z=1.11; Heidt et al., 2004).

Preliminary analysis indicates that the source on January 2, 2010 was in a high state with a gamma-ray flux (E>100MeV) of (1.4+/-0.3)x10^-6 photons cm^-2 s^-1 (error is statistical only). The flux has increased by a factor of 4 compared to the average source level during the first 11 months of the mission. Because Fermi operates in an all-sky scanning mode, regular gamma-ray monitoring of this source will continue.

The blazar PKS 0426-380 will be one of the "LAT Monitored Sources" (http://fermi.gsfc.nasa.gov/ssc/data/policy/LAT_Monitored_Sources.html), and consequently, a preliminary, uncalibrated estimation of the daily gamma-ray flux observed by Fermi LAT will be publicly available (http://fermi.gsfc.nasa.gov/ssc/data/access/).

In consideration of the ongoing activity of this source we strongly encourage multiwavelength observations. For this source the Fermi LAT contact person is Y. T. Tanaka (tanaka@astro.isas.jaxa.jp).

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.


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