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Related papers: The Gamma-Ray Properties of Unidentified EGRET Sou…

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A brief summary of the main properties of the unidentified gamma-ray sources detected by EGRET is presented, with particular emphasis on the different populations and their phenomenological characteristics.

Astrophysics · Physics 2016-11-09 G. E. Romero

The identification of celestial gamma-ray sources with astronomical objects or object classes has remained the initial and most fundamental key for understanding their physical nature. The observational characteristic of a gamma-ray emitter…

Astrophysics · Physics 2009-11-11 Olaf Reimer

The large majority of EGRET point sources remain to this day without an identified low-energy counterpart. Whatever the nature of the EGRET unidentified sources, faint unresolved objects of the same class must have a contribution to the…

Astrophysics · Physics 2008-11-26 V. Pavlidou , J. M. Siegal-Gaskins , C. Brown , B. D. Fields , A. V. Olinto

The large majority of EGRET point sources remain without an identified low-energy counterpart, and a large fraction of these sources are most likely extragalactic. Whatever the nature of the extragalactic EGRET unidentified sources, faint…

Astrophysics · Physics 2010-11-11 V. Pavlidou , J. M. Siegal-Gaskins , B. D. Fields , A. V. Olinto , C. Brown

A review of the main characteristics of low-latitude sources in the third EGRET catalog is presented. There are 75 unidentified gamma-ray sources detected by EGRET at less than 10 degrees from the galactic plane. About a half of these…

Astrophysics · Physics 2007-05-23 Gustavo E. Romero

Context. A considerable fraction of the gamma-ray sources discovered with the Energetic Gamma-Ray Experiment Telescope (EGRET) remain unidentified. The EGRET sources that have been properly identified are either pulsars or variable sources…

The 3rd EGRET catalogue lists 271 sources and provides an identification for 101 of them. Thus, the unidentified sources are the majority in the gamma-ray sky, as we currently know it. Solving the mystery of the unidentified gamma-ray…

Astrophysics · Physics 2007-05-23 P. A. Caraveo

We investigated the MeV properties of 173 unidentified or only tentatively identified EGRET sources listed in the third EGRET catalogue, by analyzing the simultaneously collected COMPTEL MeV data for each individual source. The sources can…

Astrophysics · Physics 2009-11-10 S. Zhang , W. Collmar , W. Hermsen , V. Schönfelder

We present preliminary results of a campaign undertaken with different radio interferometers to observe a sample of the most variable unidentified EGRET sources. We expect to detect which of the possible counterparts of the gamma-ray…

More than half the sources in the Third EGRET (3EG) catalog have no firmly established counterparts at other wavelengths and are unidentified. Some of these unidentified sources have remained a mystery since the first surveys of the…

Astrophysics · Physics 2015-06-24 R. Mukherjee , J. P. Halpern

In a recent paper, Romero et al. (1999) have presented the results of a positional correlation analysis of the low-latitude unidentified gamma-ray sources in the Third EGRET catalog with complete lists of galactic objects like supernova…

Astrophysics · Physics 2007-05-23 Gustavo E. Romero , Diego F. Torres , P. Benaglia , J. A. Combi , B. Punsly

The EGRET telescope has repeatedly observed 3EG J1835+5918 as a bright and steady source of high-energy gamma-ray radiation which has not yet been indentified. EGRET data from CGRO observation cycle 1 to 7 have been reanalysed above 100 MeV…

Astrophysics · Physics 2009-11-06 O. Reimer , K. T. S. Brazier , A. Carraminana , G. Kanbach , P. L. Nolan , D. J. Thompson

The EGRET instrument aboard the Compton Gamma Ray Observatory (CGRO) has completed the first all-sky survey in high-energy gamma rays and has repeatedly viewed selected portions of the sky. Analysis of the region with galactic latitude…

Astrophysics · Physics 2009-10-28 P. L. Nolan

The variability of the high-energy gamma ray sources in the Third EGRET catalog is analyzed by a new method. We re-analyze the EGRET data to calculate a likelihood function for the flux of each source in each observation, both for…

Astrophysics · Physics 2009-11-10 P. L. Nolan , W. F. Tompkins , I. A. Grenier , P. F. Michelson

The origin of the extragalactic gamma-ray background (EGRB) is still an open question, even after nearly forty years of its discovery. The emission could originate from either truly diffuse processes or from unresolved point sources.…

High Energy Astrophysical Phenomena · Physics 2009-11-09 D. Bhattacharya , P. Sreekumar , R. Mukherjee

The nature of the unidentified gamma-ray point sources in the galactic plane is a long standing puzzle of gamma-ray astronomy. Kaaret and Cottam (1996) showed that 16 of the 25 unidentified gamma-ray point sources near the galactic plane…

Astrophysics · Physics 2007-05-23 Philip Kaaret

Cosmic gamma rays provide insight into some of the most dynamic processes in the Universe. At the dawn of a new generation of gamma-ray telescopes, this review summarizes results from the Energetic Gamma Ray Experiment Telescope (EGRET) on…

Astrophysics · Physics 2009-11-13 D J Thompson

The EGRET instrument has measured detailed photon spectra between 30 MeV and 10 GeV, which are represented by means of single power-law fits for sources in the 3EG catalog. However, various sources show indications of spectral cutoffs at…

Astrophysics · Physics 2007-05-23 O. Reimer , D. L. Bertsch

The ~70 unidentified sources of the EGRET sky survey may be one of its most important legacies. The identification of these sources at other wavelengths is critical to understanding their nature. Many have flat spectra out to 10 GeV which,…

The 3rd EGRET Catalog of High-energy Gamma-ray Sources contains 170 unidentified sources, and there is great interest in the nature of these sources. One means of determining source class is the study of flux variability on time scales of…

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