Related papers: Variable Unidentified Gamma-Ray Sources Near the G…
Structure formation in the intergalactic medium (IGM) produces large-scale, collisionless shock waves, where electrons can accelerate to highly relativistic energies. Such electrons can Compton scatter cosmic microwave background photons up…
The goal of this work is to search for Active Galactic Nuclei (AGN) in the Galactic disc at very low latitudes with |b| $<$ 2$^\circ$. For this, we studied the five sources from the VVV near-infrared galaxy catalogue that have also WISE…
Recent observations of the Galactic center in high-energy gamma-rays (above 0.1TeV) have opened up new ways to study this region, from understanding the emission source of these high-energy photons to constraining the environment in which…
The unidentified EGRET source 3EG J1828+0142, located at (l,b) ~ (31.9,5.8) (Hartman et al. 1999), is particularly enigmatic since it displays very high variability over timescales of months (Torres et al. 2000, Tompkins 1999) yet no blazar…
We present a method to assess the reliability of the identification of EGRET sources with extragalactic radio sources. We verify that EGRET is detecting the blazar class of AGN. However, many published identifications are found to be…
The H.E.S.S. Galactic plane scan has revealed a large population of Galactic very high energy (VHE; E > 100 GeV) emitters. The majority of the galactic sources are extended and can typically be associated with pulsar wind nebulae (35%) and…
Within the framework of our program (running since 2004) of identification of hard X-ray INTEGRAL sources through optical spectroscopy, we present the results concerning the nature of 33 high-energy objects. The data were acquired with the…
In the paper, we continually use the method of image stacking to study the origin of the extragalactic gamma-ray background (EGB) at GeV bands, and find that the Faint Images of the Radio Sky at Twenty centimeters (FIRST) sources undetected…
We find that Gamma-ray bursts (GRBs) at the 3B catalog are correlated (at 95\% confidence level) with Abell clusters. This is the first known correlation of GRBs with any other astronomical population. It confirms the cosmological origin of…
The NuSTAR serendipitous survey has already uncovered a large number of Active Galactic Nuclei (AGN), providing new information about the composition of the Cosmic X-ray Background. For the AGN off the Galactic plane, it has been possible…
We present the results of the most comprehensive survey of the Galactic plane in very high-energy (VHE) gamma-rays, including a public release of Galactic sky maps, a catalog of VHE sources, and the discovery of 16 new sources of VHE…
A recent analysis of COMPTEL data has revealed the existence of an unidentified and variable gamma-ray source, designated GRO J1411-64, at MeV energies in the galactic plane (Zhang et al. 2002). We discuss the possibility that such a source…
Notwithstanding the advent of the Gamma-ray Large Area Telescope, theoretical models predict that a significant fraction of the cosmic gamma-ray background (CGB), at the level of 20% of the currently measured value, will remain unresolved.…
After almost 5 years of operation, ESA's International Gamma-Ray Astrophysics Laboratory (INTEGRAL) Space Observatory has unveiled a new soft Gamma ray sky and produced a remarkable harvest of results, ranging from identification of new…
The all-sky survey in high-energy gamma rays (E > 30 MeV) carried out by the Energetic Gamma Ray Experiment Telescope (EGRET) aboard the Compton Gamma-Ray Observatory provides a unique opportunity to examine in detail the diffuse gamma-ray…
The clusters of gamma-ray bursts are considered which are assumed to be images of the repeated gamma-ray burst (GRB) sources. It is shown, that localization of the cosmic gamma-ray burst sources (GBS) is determined by the clusters of GRBs.…
Recent observations with atmospheric Cherenkov telescope systems such as H.E.S.S. and MAGIC have revealed a large number of new sources of very-high-energy (VHE) gamma-rays from 100 GeV - 100 TeV, mostly concentrated along the Galactic…
We present the results of an all-sky radio survey between 5 and 9 GHz of the fields surrounding all unassociated gamma-ray objects listed in the Fermi Large Area Telescope Second Source Catalog (2FGL). The goal of these observations is to…
Statistical arguments show that the volume- and time-averaged kinetic power of GRBs and fireball transients (FTs) into an L* galaxy like the Milky Way is at the level of 10^40 ergs/s. This number, though with wide uncertainties related to…
We discuss the diffuse emission of gamma rays and neutrinos from galaxy clusters in the viable models for structure formation in the universe. We use a self-consistent picture for cluster formation and evolution starting from a primordial…