Related papers: Low-latitude gamma-ray sources: correlations and v…
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…
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…
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 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…
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…
We present a study on the possible association of unidentified $\gamma$-ray sources in the Third EGRET (3EG) catalog with different types of galactic objects such as Wolf-Rayet and Of stars, supernova remnants (SNRs), and OB associations…
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…
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…
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…
The vast majority of the celestial gamma-ray sources detected so far have not yet been identified with secure counterparts at other wavelenghts. Here we report the preliminary evidence of a probable association between galaxy clusters and…
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…
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…
A subset of the unidentified EGRET gamma-ray sources with no active galactic nucleus or other conspicuous counterpart appears to be concentrated at medium latitudes. Their long-term variability and their spatial distribution indicate that…
Some phenomenological properties of the unidentified EGRET detections suggest that there are two distinct groups of galactic gamma-ray sources that might be associated with compact objects endowed with relativistic jets. We discuss…
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…
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…
Using survey data, we have re-evaluated the correlation of flat spectrum radio sources with EGRET sources in the Northern sky. A likelihood analysis incorporating the radio and X-ray properties and the Gamma-ray source localization is used…
Most counterparts of the identified low-latitude gamma-ray sources are Isolated Neutron Stars (INSs). They are characterized by an extremely high value of the X/optical flux ratio, therefore a systematic X-ray/optical coverage of the fields…
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…
Microquasars are promising candidates to emit high-energy gamma-rays. Moreover, statistical studies show that variable EGRET sources at low galactic latitudes could be associated with the inner spiral arms. The variable nature and the…