Related papers: High-mass microquasars and low-latitude gamma-ray …
Millisecond pulsars have been discussed as a possible source of the gamma-ray excess observed from the region surrounding the Galactic Center. With this in mind, we use the observed population of bright low-mass X-ray binaries to estimate…
"Diffuse" gamma rays consist of several components: truly diffuse emission from the interstellar medium, the extragalactic background, whose origin is not firmly established yet, and the contribution from unresolved and faint Galactic point…
Violent multi-wavelength variabilities are observed in gamma-ray-selected blazars. We present an analysis of long-term light curves for eight bright blazars to explore the co-variation pattern in the gamma-ray and radio bands. We extract…
The launch of the Fermi gamma-ray space telescope and the imaging air Cerenkov telescopes H.E.S.S., MAGIC, and VERITAS have substantially transformed our knowledge of gamma-ray sources in the last decade. The extragalactic gamma-ray sky is…
The BATSE experiment has now observed more than 1100 gamma-ray bursts. The observed angular distribution is isotropic, while the brightness distribution of bursts shows a reduced number of faint events. These observations favor a…
In the time domain, the radio sky in particular along the Galactic plane direction may vary significantly because of various energetic activities associated with stars, stellar and supermassive black holes. Using multi-epoch Very Large…
Recent EGRET observations of the diffuse Galactic gamma-ray emission reveal a spectrum which is incompatible with the assumption that the cosmic ray spectra measured locally hold throughout the Galaxy: the spectrum above 1 GeV, where the…
We present a study of the compatibility of some current models of the diffuse Galactic continuum gamma rays with EGRET data. A set of regions sampling the whole sky is chosen to provide a comprehensive range of tests. The range of EGRET…
Microquasars are accreting X-ray binary systems with non-thermal radio jets. In some of these systems the jet is expected to be strongly misaligned with the perpendicular to the orbital plane. If the donor star is an early-type star, the…
We report on preliminary results from the Fermi High-Latitude Extended Sources Catalog (FHES), a comprehensive search for spatially extended gamma-ray sources at high Galactic latitudes ($|b|>5^\circ$) based on data from the Fermi Large…
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…
Fermi/LAT observations of star-forming galaxies in the ~0.1-100GeV range have made possible a first population study. Evidence was found for a correlation between gamma-ray luminosity and tracers of the star formation activity. Studying…
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.…
Using gamma-ray data from the Fermi Large Area Telescope, various groups have identified a clear excess emission in the Inner Galaxy, at energies around a few GeV. This excess resembles remarkably well a signal from dark-matter…
Gamma-ray emission in active galaxies is likely produced within the inner jet, or in the close vicinity of the supermassive black hole (SMBH) at sub-parsec distances. Gamma rays have to pass through the surrounding massive stellar cluster…
X-ray and gamma-ray binaries are systems consisting of a compact object and normally a non-degenerate companion star. Most of these sources have been shown to emit radiation in a broad frequency range, from radio up to X-rays and sometimes…
Pulsars are factories of relativistic electrons and positrons that propagate away from the pulsar, permeating later our Galaxy. The acceleration and propagation of these particles are a matter of intense debate. In the last few years, we…
We search for gamma-ray emission from 114 Galactic high mass X-ray binaries, including 4 well studied catalogued sources, in 12.5 years of Fermi-LAT data in conjunction with the 10-year point source catalogue. Where a gamma-ray excess…
We address the role of gamma-ray astronomy in the investigation of nonthermal processes in the large scale structure of the universe. Based on EGRET upper limits on nearby galaxy clusters (GCs) we constrain the acceleration efficiency of CR…
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…