Related papers: Cosmic rays: interstellar gamma-ray and radio emis…
Possible formulations of the problem of cosmic rays acceleration in the interstellar galactic medium are considered with the use of fractional differential equations. The applied technique has been physically justified. A Fermi result has…
Gamma rays from distant blazars interact with the extragalactic background light, creating electron-positron pairs, and reducing the gamma-ray flux measured by ground-based atmospheric Cherenkov gamma-ray telescopes. These pairs can…
Gamma-Ray Bursts are likely associated with a catastrophic energy release in stellar mass objects. Electromagnetic observations provide important, but indirect information on the progenitor. On the other hand, gravitational waves emitted…
Recent data from ATIC, CREAM and PAMELA indicate that the cosmic ray energy spectra of protons and nuclei exhibit a remarkable hardening at energies above 100 GeV per nucleon. We propose that the hardening is an interstellar propagation…
The contributions of different radiation mechanisms to the diffuse gamma-ray emission of the galactic disk are studied in a broad energy region from X-rays to very high energy gamma rays.
We show that inverse Compton scattering of cosmic-microwave-background and starlight photons by cosmic-ray electrons in the interstellar and intergalactic space explains well the spectrum and intensity of the diffuse gamma-ray background…
Ever since the discovery of Cosmic Rays (CRs), significant advancements have been made in modeling their propagation in the Galaxy and in the Heliosphere. However, propagation models suffer from degeneracy of many parameters. To complicate…
Using data obtained as part of the {\it Spitzer} Infrared Nearby Galaxies Survey (SINGS; Kennicutt et al. 2003) and WSRT-SINGS radio continuum survey (Braun et al. 2006), we study the effects of star-formation activity on the far-infrared…
We present the first interpretation of the new isotropic diffuse gamma-ray background (IGRB), measured by the Fermi Large Area Telescope (LAT), based on a statistical analysis. We demonstrate that the gamma-ray emission from unresolved…
We discuss the degree to which radio propagation measurements diagnose conditions in the ionized gas of the interstellar medium (ISM). The "signal generators" of the radio waves of interest are extragalactic radio sources (quasars and radio…
We report the detection of the lunar gamma-ray emission during the first year of Fermi-LAT observations. Such emission is produced by cosmic ray nuclei interacting with the lunar surface. Thanks to the solar minimum conditions and the…
We investigate the neutrino - cosmic ray connection for sources in the Galaxy in terms of two observables: the shape of the energy spectrum and the distribution of arrival directions. We also study the associated gamma ray emission from…
Recent observations of high ionization rates of molecular hydrogen in diffuse interstellar clouds point to a distinct low-energy cosmic-ray component. Supposing that this component is made of nuclei, two models for the origin of such…
Recent results, the present status and the perspectives of high energy gamma-ray astronomy are described. Since the satellite observations by the Compton Gamma Ray Observatory and its precursor missions have been reviewed extensively,…
Interaction of cosmological gamma ray burst radiation with the dense interstellar medium of host galaxy is considered. Gas dynamical motion of interstellar medium driven by gamma ray burst is investigated in 2D approximation for different…
Gamma-ray bursts are short-lived, luminous explosions at cosmological distances, thought to originate from relativistic jets launched at the deaths of massive stars. They are among the prime candidates to produce the observed cosmic rays at…
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…
The Universe is largely transparent to $\gamma$ rays in the GeV energy range, making these high-energy photons valuable for exploring energetic processes in the cosmos. After seven years of operation, the Fermi {\it Gamma-ray Space…
Cosmic rays (CRs) in the Galaxy are an important dynamical component of the interstellar medium (ISM) that interact with the other major components (interstellar magnetic and radiation fields, and gas) to produce broadband interstellar…
The physics results of high energy gamma-ray astronomy are reported, emphasizing recent achievements with ground-based detectors. This includes some of the instrumental developments and latest projects. The fundamental contribution of the…