The Third EGRET Catalog of High‐Energy Gamma‐Ray Sources

Abstract

The third catalog of high-energy gamma-ray sources detected by the EGRET telescope on the Compton Gamma Ray Observatory includes data from 1991 April 22 to 1995 October 3 (cycles 1, 2, 3, and 4 of the mission). In addition to including more data than the second EGRET catalog and its supplement, this catalog uses completely reprocessed data (to correct a number of mostly minimal errors and problems). The 271 sources (E [ 100 MeV) in the catalog include the single 1991 solar Ñare bright enough to be detected as a source, the Large Magellanic Cloud, Ðve pulsars, one probable radio galaxy detection (Cen A), and 66 high-conÐdence identiÐcations of blazars (BL Lac objects, Ñat-spectrum radio quasars, or unidentiÐed Ñat-spectrum radio sources). In addition, 27 lower conÐdence potential blazar identiÐcations are noted. Finally, the catalog contains 170 sources not yet identiÐed Ðrmly with known objects, although potential identiÐcations have been suggested for a number of those. A Ðgure is presented that gives approximate upper limits for gamma-ray sources at any point in the sky, as well as information about sources listed in the second catalog and its supplement, that do not appear in this catalog.

Radio properties of the γ ‐ray emitting CSO candidate 2234+282

“…Its optical spectrum was described by Shaw et al (2012) as transitional between flat-spectrum quasars and BL Lac type objects. It was detected by Fermi with a statistical significance of 52.1σ, corresponding to 3FGL J2236.3+2829 and 2FGL J2236.4+2828 (Acero et al, 2015), but not detected by the Energetic Gamma Ray Experiment Telescope (EGRET; Hartman et al, 1999) of the Compton Gamma Ray Observatory, probably due to insufficient sensitivity.…”

Application of the MST clustering to the high energy γ $\gamma$ -ray sky. I—New possible detection of high-energy γ $\gamma$ -ray emission associated with BL Lac objects

“…Note that this object was already reported as a possible counterpart to 3EG J1424+3734 in the Third EGRET catalogue (Hartman et al 1999), although at a distance of about 21 . It was also present in 1FGL and 1LAC (Abdo et al 2010) catalogues, but disappeared in the subsequent versions.…”

Neutrino signals from galactic binaries

“…We will adopt f p ∼ 0.1, in order to reproduce the observed gamma-ray flux at GeV energies, where opacity effects due to pair creation are unimportant. A value of α = 2.2 characterizes the power law spectrum matching the GeV gammaray spectrum observed by EGRET [35]. Note that θ will be roughly the same as that of the emerging photon (θ ≈ θ obs ) [22].…”