Related papers: Unresolved Unidentified Source Contribution to the…
The detection by the HESS atmospheric Cherenkov telescope of fifteen new sources from the Galactic plane makes it possible to estimate the contribution of unresolved point sources like those detected by HESS to the diffuse Galactic emission…
Despite the influx of unprecedented-quality data from the Fermi Gamma-Ray Space Telescope that have been collected over nine years of operation, the contribution of normal star-forming galaxies to the extragalactic gamma-ray background…
B2013+370 and B2023+336 are two blazars at low-galactic latitude that were previously proposed to be the counterparts for the EGRET unidentified sources, 3EG J2016+3657 and 3EG J2027+3429. Gamma-ray emission associated with the EGRET…
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 revisit the association of unidentified Galactic plane EGRET sources with tracers of recent massive star formation and death. Up-to-date catalogs of OB associations, SNRs, young pulsars, HII regions and young open clusters were used in…
The Galactic gamma-ray flux can be described as the sum of two components: the first is due to the emission from an ensemble of discrete sources, and the second is formed by the photons produced by cosmic rays propagating in interstellar…
The Galactic diffuse emission is potentially able to reveal much about the sources and propagation of cosmic rays (CR), their spectra and intensities in distant locations. It can possibly unveil WIMP dark matter (DM) through its…
We use the recent measurement of the isotropic $\gamma$-ray background (IGRB) by Fermi LAT and analysis of the contribution of unresolved point $\gamma$-ray sources to IGRB to build constraints on the models of ultra-high cosmic rays…
The GALPROP model for cosmic-ray propagation is able to make explicit predictions for the distribution of galactic diffuse gamma-rays. We compare different propagation models with gamma-ray spectra measured by EGRET for various regions of…
There is active interest in the extent to which unresolved gamma-ray pulsars contribute to the galactic diffuse emission, and whether unresolved gamma-ray pulsars could be responsible for the excess of diffuse galactic emission above 1 GeV…
Structure formation in the universe can produce high energy gamma-rays from shock-accelerated electrons, and this process may be the origin of the extragalactic gamma-ray background (EGRB) as well as a part of the unidentified sources…
Observations of distant gamma-ray sources are hindered by the presence of the extragalactic background light (EBL). In order to understand the physical processes that result in the observed spectrum of sources, it is imperative that a good…
In a novel approach in observational high-energy gamma-ray astronomy, observations carried out by imaging atmospheric Cherenkov telescopes provide necessary templates to pinpoint the nature of intriguing, yet unidentified EGRET gamma-ray…
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…
Revealing the nature of unassociated high-energy (> 100 MeV) gamma-ray sources remains a challenge 35 years after their discovery. Of the 934 gamma-ray sources at high Galactic latitude (|b| > 15 degrees) in the First Fermi-LAT catalogue…
The COMPTEL and EGRET detectors aboard the Compton Gamma-Ray Observatory measured an extragalactic gamma-ray background extending from MeV energies up to about 100 GeV. Calculations performed making reasonable assumptions indicate that…
We study the origin of the extragalactic diffuse gamma-ray background using the data from the Fermi telescope. To estimate the background level, we count photons at high Galactic latitudes |b|>60 degrees. Subtracting photons associated to…
We present a new theoretical calculation of the contribution to the extragalactic gamma-ray background radiation (EGRB) from star-forming galaxies, based on a state-of-the-art model of hierarchical galaxy formation that is in quantitative…
The identification of point sources poses a great challenge for the high energy community. We present a new approach to evaluate the likelihood of a set of sources being a Galactic population based on the simple assumption that galaxies…
An Isotropic Diffuse Gamma-Ray Background (IDGRB) in the spectral range 30-10,000 MeV was first reported in the early 1970's using measurements made by the SAS-2 instrument. Data recorded by the Energetic Gamma Ray Experiment Telescope…