High Galactic latitude Fermi sources of γ-rays with energies above 100 GeV

¹ ISDC Data Centre for Astrophysics, Ch. d’Ecogia 16, 1290 Versoix, Switzerland
e-mail: Andrii.Neronov@unige.ch
² APC, 10 rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13, France
e-mail: dmitri.semikoz@apc.univ-paris7.fr
³ Institute for Nuclear Research RAS, 60th October Anniversary prosp. 7a, Moscow 117312, Russia

Received: 4 August 2010
Accepted: 6 February 2011

Abstract

Aims. We present a catalog of sources of very high energy (E > 100 GeV) γ-rays detected by the Large Area Telescope (LAT) onboard the Fermi Gamma-Ray Space Telescope at Galactic latitudes |b| ≥ 10°.

Methods. We cross-correlate the directions of individual photons with energies above 100 GeV detected by Fermi /LAT with the first year Fermi catalog of sources detected at lower energies. We find a significant correlation between the arrival directions of the highest energy photons and positions of Fermi sources, with the possibility of chance coincidences at the level of 10^-45. We present a list of Fermi sources contributing to the correlation signal. A similar analysis is performed to cross-correlate the catalog of BL Lac objects with the highest energy photons detected by Fermi.

Results. We produce a catalog of high Galactic latitude Fermi sources visible at 100 − 300 GeV energies. The catalog is divided into two parts. The first part contains a list of 50 higher significance sources among which there can be three possible false detections. The second part of the catalog contains a list of 25 lower significance sources, among which six are possibly false detections. Finally we identify eight additional sources from the cross-correlation analysis with the BL Lac catalog. The reported sources of E > 100 GeV γ-rays span a broad range of redshifts, up to z ~ 1. Most of the sources are BL Lac type objects. Only 17 out of 83 objects in our list were previously reported as VHE γ-ray sources.