Related papers: Cosmic Rays and Non-Thermal Emission in Galaxy Clu…
Cosmic rays produce molecular cluster ions as they pass through the lower atmosphere. Neutral molecular clusters such as dimers and complexes are expected to make a small contribution to the radiative balance, but atmospheric absorption by…
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…
Thermal X-ray spectra of clusters of galaxies and other sources are commonly calculated assuming Maxwellian electron distributions. There are situations where this approximation is not valid, for instance near interfaces of hot and cold gas…
Diffusive TeV gamma-ray emissions have been recently discovered extending beyond the pulsar wind nebulae of a few middle-aged pulsars, implying that energetic electron/positron pairs are escaping from the pulsar wind nebulae and radiating…
The Fermi satellite has recently detected gamma ray emission from the central regions of our Galaxy. This may be evidence for dark matter particles, a major component of the standard cosmological model, annihilating to produce high-energy…
The study of soft X-ray emission of 38 X-ray selected galaxy clusters observed by ROSAT PSPC indicates that the soft excess phenomenon may be a common occurrence in galaxy clusters. Excess soft X-ray radiation, above the contribution from…
There is now firm evidence that the ICM consists of a mixture of hot plasma, magnetic fields and relativistic particles. The most important evidences for non-thermal phenomena in galaxy clusters comes from the diffuse Mpc-scale synchrotron…
The radiative cooling time of the X-ray-emitting plasma near the center in many clusters of galaxies is shorter than the age of the cluster, but neither the expected large drop in central temperature --nor the expected mass flow towards the…
Jets are ubiquitous in the Universe. They are collimated outflows whose origin is associated to an accretion disc and a central object, and can be very powerful non-thermal emitters. Jets form in active galactic nuclei, gamma-ray bursts,…
A new theory for gamma-ray burst radiation is presented. In this theory, magnetic fields and relativistic electrons are created through plasma processes arising as a relativistic shell passes through the interstellar medium. The gamma-rays…
Accelerated particles are ubiquitous in the Cosmos and play a fundamental role in many processes governing the evolution of the Universe at all scales, from the sub-AU ones relevant for the formation and evolution of stars and planets to…
Formation of dark matter halos is sensitive to the expansion rate of the Universe and to the growth of structures under gravitational collapse. Virialization of halos heats the gaseous intra-cluster medium to high temperatures, leading to…
The powerful wind-wind collision in massive star binaries creates a region of high temperature plasma and accelerates particles to relativistic energies. I briefly summarize the hydrodynamics of the wind-wind interaction and the…
The successful discovery of X-ray, optical and radio afterglows of GRB has made possible the identification of host galaxies at cosmological distances. The energy release inferred in these outbursts place them among the most energetic and…
Cosmic rays fill up the entire volume of galaxies, providing an important source of heating and ionisation of the interstellar medium, and may play a significant role in the regulation of star formation and galactic evolution. Diffuse…
Galaxy clusters are the most massive constituents of the large-scale structure of the Universe. While the hot thermal gas that pervades galaxy clusters is relatively well understood through observations with X-ray satellites, our…
We present an MHD simulation of the emergence of a radio minihalo in a galaxy cluster core in a "secondary" model, where the source of the synchrotron-emitting electrons is hadronic interactions between cosmic-ray protons with the thermal…
Galaxy clusters are predicted to produce gamma-rays through cosmic ray interactions and/or dark matter annihilation, potentially detectable by the Fermi Large Area Telescope (Fermi-LAT). We present a new, independent stacking analysis of…
We calculate the high-energy gamma-ray and neutrino emissions from galaxy clusters like Perseus that host active galactic nuclei (AGNs). Our primary objective is to distinguish the emission from the central source, such as NGC$1275$, from…
The astrophysical $\gamma$-ray photons carry the signatures of the violent phenomena happening on various astronomical scales in our Universe. This includes supernova remnants, pulsars, and pulsar wind nebulae in the Galactic environment…