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Discovery of VHE gamma-ray emission from PKS 0301-243 with Fermi

ATel #2610; A. Neronov (ISDC) D. Semikoz (APC), Ie. Vovk (ISDC)
on 11 May 2010; 10:14 UT
Credential Certification: Andrii Neronov (andrii.neronov@obs.unige.ch)

Subjects: Gamma Ray, >GeV, AGN

We report the discovery of VHE (E>100 GeV) emission from the BL Lac type blazar PKS 0301-243 (z=0.26, RA 03:03:26.50, DEC -24:07:11.5, J2000). Evidence for the VHE gamma-ray emission from this source was previously found in the 100-300 GeV band data of Fermi telescope (Neronov et al. arXiv:1004.3767). The source has recently experienced a bright flare in the energy band above 100 MeV detected by Fermi telescope (Cannon A., ATEL #2591). We have analyzed Fermi data collected during the period between April 29 and May 7, 2010, corresponding to the flare, and found that the flaring activity of the source was accompanied by gamma-ray emission in the VHE energy band with the source flux reaching the level of ~1 Crab unit at the energies above 100 GeV. The overall significance of detection of the source above 100 GeV is 6.8 sigma (the standard Fermi likelihood analysis of the entire Fermi exposure starting from August 4, 2008, gives the Test Statistics value TS=45.7 at the source position in the 100-300 GeV energy band ). Additional information about the source properties (TS map, lightcurve and spectrum) could be found at http://www.isdc.unige.ch/vhe/Objects/1FGL_J0303.5-2406/page.html