Related papers: Galactic centre star formation writ large in gamma…
Accreting black holes are believed to be sites of possible particle acceleration with favorable conditions also for effective gamma-ray production. However, because of photon-photon pair production, only low energy (MeV) gamma-rays can…
We compute the production of cosmic rays in the dynamical superbubble produced by a cluster of massive stars. Stellar winds, supernova remnants and turbulence are found to accelerate particles so efficiently that the nonlinear feedback of…
The diffuse TeV emission detected from the inner $\sim2^\circ$ of the Galaxy appears to be strongly correlated with the distribution of molecular gas along the Galactic ridge. Although it is not yet entirely clear whether the origin of the…
This paper investigates the distribution and implications of cosmic ray electrons within the intergalactic medium (IGM). Utilizing a synthesis model of the extragalactic background, we evolve the spectrum of Compton-included cosmic rays.…
The Fermi Bubbles are gamma-ray structures extending from the center of the Milky Way to +/-50 degree Galactic latitude that were discovered in data obtained by the Fermi/LAT instrument. Their origin and power source remain uncertain. To…
Recent measurements of cosmic gamma ray intensities up to TeV energies have been used to estimate the spectral shape of the parent cosmic ray particles present in the interstellar medium. The case is made for the particle spectrum in the…
Here we propose that the excess flux of particle events of energy near 1 EeV from the direction of the Galactic Center region is due to the production of cosmic rays by the last few Gamma Ray Bursts in our Galaxy. The basic idea is that…
Cosmic rays up to at least PeV energies are usually described in the framework of an elementary scenario that involves acceleration by objects that are located in the disk of the Milky Way, such as supernova remnants or massive star-forming…
Studies of Fermi data indicate an excess of GeV gamma rays around the Galactic center (GC), possibly due to dark matter. We show that young gamma-ray pulsars can yield a similar signal. First, a high concentration of GC supernovae naturally…
The origin of the X-ray emission from the central region of the Galaxy has remained a mystery, despite extensive study over the past two decades. A fundamental question is the relative contribution of the point-source and diffuse components…
The bulk of the diffuse galactic gamma-ray emission above a few tens of GeV has been conventionally ascribed to the decay of neutral pions produced in cosmic-ray interactions with interstellar matter. Cosmic-ray electrons may, however, make…
We exploit XMM-Newton archival data in a study of the extended X-ray emission emanating from the Galactic Centre (GC) region. EPIC-pn and EPIC-MOS observations, with a total exposure approaching 0.5 and 1 Ms respectively, were used to…
Extended and delayed emission around distant TeV sources induced by the effects of propagation of gamma rays through the intergalactic medium can be used for the measurement of the intergalactic magnetic field (IGMF). We search for delayed…
The centre of our Galaxy is one of the most studied and yet enigmatic places in the Universe. At a distance of about 8 kpc from our Sun, the Galactic centre (GC) is the ideal environment to study the extreme processes that take place in the…
An anomalous gamma-ray excess emission has been found in Fermi Large Area Telescope data covering the centre of the Galaxy. Several theories have been proposed for this `Galactic Centre Excess'. They include self-annihilation of dark matter…
We determine upper limits on the dark matter (DM) self-annihilation cross section for scenarios in which annihilation leads to the production of electron--positron pairs. In the Galactic centre (GC), relativistic electrons and positrons…
Context: Cosmic-ray propagation is strongly dependent on the large-scale configuration of the Galactic magnetic field. In particular, the Galactic center (GC) region provides highly interesting cosmic-ray data from gamma-ray maps and it is…
After discovery of the Fermi bubbles, giant structures observed in radio to X-rays have been discussed as possi- ble evidence of past activities in the Galactic Center (GC). We report here on the analysis of Suzaku data pointing around the…
The masses of clusters of galaxies estimated by gravitational lensing exceed in many cases the mass estimates based on hydrostatic equilibrium. This may suggest the existence of nonthermal pressure. We ask if radio galaxies can heat and…
We study the advection effect of the Galactic wind on the local cosmic ray spectra. The spectral hardening from a few hundred GV and softening from a few TV are reproduced by a velocity profile with a maximum velocity of $\sim…