English
Related papers

Related papers: Variability of EGRET Gamma-Ray Sources

200 papers

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…

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…

We compute the variation of the beaming fraction with the efficiency of high energy gamma-ray production in the outer gap pulsar model of Romani and Yadigaroglu. This allows us to correct the fluxes observed for pulsars in the EGRET band…

Astrophysics · Physics 2009-10-22 I. -A. Yadigaroglu , Roger W. Romani

At the end of the EGRET mission, only 6-8 Galactic sources had been identified as young pulsars. Since then, several energetic pulsars have been discovered in EGRET error boxes along the Galactic plane, as well as several pulsar wind…

Astrophysics · Physics 2009-11-10 Mallory S. E. Roberts

Population studies of EGRET gamma-ray sources indicate that there is a distinctive population of bright sources at low galactic latitudes. The sources have a distribution consistent with that of young galactic objects, with a concentration…

Astrophysics · Physics 2009-11-10 Valenti Bosch-Ramon , Gustavo E. Romero , Josep M. Paredes

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 largest group of sources identified by EGRET are Blazars. This sub-class of AGN is well known to vary in flux in all energy bands on time-scales ranging from a few minutes (in the optical and X-ray bands) up to decades (radio and…

Astrophysics · Physics 2009-10-30 Stefan J. Wagner , Corinna von Montigny , Martin Herter

We analyze average gamma-ray variability statistics for the sample of blazars detected by CGRO/EGRET. We re-reduce all the available EGRET observations and analyze light curves by Monte Carlo modeling of the variability statistics including…

Astrophysics · Physics 2007-05-23 P. Magdziarz , R. Moderski , G. M. Madejski

The third EGRET catalog contains a large number of unidentified sources. This subset of objects is expected to include known gamma-ray emitters of Galactic origin such as pulsars and supernova remnants, in addition to an extragalactic…

Astrophysics · Physics 2009-03-26 J. M. Siegal-Gaskins , V. Pavlidou , A. V. Olinto , C. Brown , B. D. Fields

We present a catalog of point gamma-ray sources detected by the EGRET detector aboard the Compton Gamma Ray Observatory. We have used the whole gamma-ray dataset of reprocessed photons at energies above 100 MeV together with new Galactic…

Astrophysics · Physics 2009-11-13 Jean-Marc Casandjian , Isabelle A. Grenier

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

Statistical studies indicate that the 271 point sources of high-energy gamma rays belong to two groups: a Galactic population and an isotropic extragalactic population. Many unidentified extragalactic sources are certainly blazars, and it…

Astrophysics · Physics 2009-11-10 P. M. Wallace , S. D. Bloom , M. S. Lewis

We present a study of 40 low-latitude unidentified 3EG gamma-ray sources which were found to be not positionally coincident with any known class of potential gamma-ray emitters in the Galaxy (Romero, Benaglia & Torres, 1999). We have…

We have begun to examine the EGRET database for short term variations in the fluxes of blazars and unidentified sources at high Galactic latitude. We find that several AGN show previously unreported variability. Such variations are…

Astrophysics · Physics 2009-10-30 S. D. Bloom , D. J. Thompson , R. C. Hartman , C. von Montigny

This Chapter provides a review of $\gamma$-ray sources lying at high Galactic latitudes. Their statistical properties and variability status, as well as studies involving cross correlations with lower frequency catalogs and multiwavelength…

Astrophysics · Physics 2007-05-23 Diego F. Torres

Although the majority of gamma-ray sources still remain unidentified, we have various kinds of information to characterize the observational properties of unidentified EGRET sources. Despite astronomical properties like locations of…

Astrophysics · Physics 2016-01-27 Olaf Reimer

High-energy gamma-ray emission from the Galactic plane above ~100 MeV is composed of three main contributions: diffuse emission from cosmic ray interactions in the interstellar medium, emission from extended sources, such as supernova…

High Energy Astrophysical Phenomena · Physics 2015-06-05 A. Neronov , D. Malyshev , M. Chernyakova , A. Lutovinov

The field of gamma ray astronomy relies heavily on the statistical analysis of data. Because of the paucity of data, and the often large errors associated with detecting gamma rays, analysis and interpretation of the data require…

Astrophysics · Physics 2007-05-23 W. F. Tompkins

We describe the properties of the blazars detected by EGRET and summarize the results on the calculations of the evolution and luminosity function of these sources. Of the large number of possible origins of extragalactic diffuse gamma-ray…

Astrophysics · Physics 2009-10-31 R. Mukherjee , J. Chiang
‹ Prev 1 2 3 10 Next ›