Related papers: Gamma rays from the Galactic Centre region: a revi…
Despite mounting evidence that dark matter (DM) exists in the Universe, its fundamental nature remains unknown. We present sensitivity estimates to detect DM particles with a future very-high-energy ($\gtrsim$ TeV) wide field-of-view…
A recent study of the diffuse $\gamma$-ray emission in the Central Molecular Zone using very high energy (VHE, E $>$ 0.1 TeV) H.E.S.S. data suggests that the Galactic Center (GC) is the most plausible supplier of Galactic ultra-relativistic…
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 little we do know of the physical conditions in gamma-ray bursters makes them conducive to the acceleration of high-energy cosmic rays, especially if they are at cosmological distances. We find that, with the observed statistics and…
Presently there are several classes of detected gamma-ray extragalatic sources. They are mostly associated to active galactic nuclei (AGN) and (at soft gamma rays) to gamma-ray bursts (GRB), but not only. Active galactic nuclei consist of…
Gamma rays constitute a privileged point of view for the study of the extreme Universe. Unlike charged cosmic rays, which are thought to have a common origin, gamma rays are not deflected by galactic and intergalactic magnetic fields. This…
Continuum low-frequency radio observations of the Galactic Center reveal the presence of two prominent radio sources, Sgr A East and its surrounding Halo, containing non-thermal particle distributions with power-law indices around 2.5-3.3…
The diffuse Galactic $\gamma$-ray emission, mainly produced via interactions between cosmic rays and the interstellar medium and/or radiation field, is a very important probe of the distribution, propagation, and interaction of cosmic rays…
Among all the high-energy environments of our Galaxy, the Galactic Center (GC) region is definitely the richest. It harbors a large amount of non-thermal emitters, including the closest supermassive black hole, dense molecular clouds,…
Very high energy (VHE) gamma-rays have been detected from the direction of the Galactic center. The H.E.S.S. Cherenkov telescopes have located this gamma-ray source with a preliminary position uncertainty of 8.5" per axis (6" statistic + 6"…
Clusters of galaxies are believed to contain a significant population of cosmic rays. From the radio and probably hard X-ray bands it is known that clusters are the spatially most extended emitters of non-thermal radiation in the Universe.…
Diffuse VHE gamma radiation from the Galactic Centre ridge observed by the H.E.S.S. telescope has been convincingly linked with the propagation of recently accelerated cosmic rays that interact with molecular hydrogen clouds during their…
The center of the our Galaxy is a region where very energetic phenomena take place. In particular powerful cosmic ray sources can be located in that region. The cosmic rays accelerated in these sources may interact with ambient protons…
In spite of increasing evidences of the presence of a massive Black Hole at the Galactic Center, its radio counterpart, Sgr A*, shows little activity at high energies, and recent models involving energy advection (ADAF) have been proposed…
The last decade has been dense with new developments in the search for the sources of Galactic cosmic rays. Some of these developments have confirmed the tight connection between cosmic rays and supernovae in our Galaxy, through the…
We analyze the possibility that the HESS gamma-ray source at the Galactic Center could be explained as the secondary flux produced by annihilation of TeV Dark Matter (TeVDM) particles with locally enhanced density, in a region spatially…
We consider the emission of high energy to very high energy $\gamma$-rays in radio-quiet active galactic nuclei (AGN) or the central regions of radio-loud AGN. We use our results to estimate the $\gamma$-ray flux from the central regions of…
The production of very-high-energy (VHE, $E_{\gamma} \gtrsim 100$ GeV) gamma rays resulting from the scattering of high-energy cosmic-ray protons off axion-like particles (ALPs) populating the dark matter halo of the Milky Way is…
Motivated by the gamma-ray excess observed from the region surrounding the Galactic Center, we explore particle dark matter models that could potentially account for the spectrum and normalization of this signal. Taking a model-independent…
Observations by the H.E.S.S. system of imaging atmospheric Cherenkov telescopes provide the most sensitive measurements of the Galactic Centre region in the energy range 150 GeV - 30 TeV. The vicinity of the kinetic centre of our galaxy…