Related papers: On the Temporal Variability of the Galactic Multi-…
The diffuse gamma-ray emission between 10 and 1000 TeV from the Galactic plane was recently measured by the Large High Altitude Air Shower Observatory (LHAASO). These observations will help tremendously in constraining the propagation and…
GeV and TeV emission from the forward shocks of supernova remnants (SNRs) indicates that they are capable particle accelerators, making them promising sources of Galactic cosmic rays (CRs). However, it remains uncertain whether this…
Supernova remnants (SNRs) are thought to be the primary sources of Galactic Cosmic Rays (CRs). In the last few years, the wealth of gamma-ray data collected by GeV and TeV instruments has provided important information about particle…
We revisit propagation of galactic cosmic rays (CRs) in light of recent advances in CR diffusion theory in realistic interstellar turbulence. We use a tested model of turbulence in which it has been shown that fast modes dominate scattering…
The quest for the origin of cosmic ray (CRs) is a fundamental issue in astrophysics. Shocks of supernova remnants (SNRs) have been considered as the dominant contributors to Galactic CRs below the spectral knee near $\sim 3$…
The acceleration mechanisms of cosmic rays (CR) in supernova remnants (SNRs) and their associated compact central objects (CCOs) remain an open question in high-energy astrophysics. In this study, we perform a modeling of CR transport and…
We study the decays of ultraheavy (m_X \geq 10^{13}GeV) and quasistable (lifetime \tau_X much larger than the age of the Universe t_0) particles as the source of Ultra High Energy Cosmic Rays (UHE CR). These particles are assumed to…
Various studies have implied the existence of a gaseous halo around the Galaxy extending out to 100 kpc. Galactic cosmic rays (CRs) that propagate to the halo, either by diffusion or by convection with the possibly existing large-scale…
Various studies firmly establish the fact that gamma-ray observations can act as a unique probe to detect the possible cosmic ray (CR) sources, study the CR density distribution and explore the average properties of interstellar medium…
The High Energy Stereoscopic System (HESS), the Major Atmospheric Gamma-ray Imaging Cherenkov Telescope (MAGIC), and the Very Energetic Radiation Imaging Telescope Array System (VERITAS) have observed diffuse gamma-ray emission strongly…
The $\gamma$-ray emission of star-forming (SF) galaxies is attributed to hadronic interactions of cosmic ray (CR) protons with the interstellar gas and contributions from CR electrons via bremsstrahlung and inverse Compton (IC) scattering.…
Diffuse Galactic gamma-ray emission is produced in interactions of cosmic rays with gas and ambient photon fields and thus provides us with an indirect measurement of cosmic rays in various locations in the Galaxy. The diffuse gamma-ray…
Galactic cosmic rays (CRs) are accelerated by astrophysical shocks, primarily supernova remnants (SNRs), via diffusive shock acceleration (DSA), an efficient mechanism that predicts power-law energy distributions of CRs. However,…
The ultra high-energy (UHE) Galactic diffuse gamma-ray emission holds important information on the propagation of cosmic rays in the Galaxy. However, its measurements suffer from a contamination from unresolved sources whose contribution…
A model for high-energy (>10^14 eV) cosmic rays (HECRs) from galactic and extragalactic gamma-ray bursts (GRBs) is summarized. Relativistic outflows in GRBs are assumed to inject power-law distributions of CR protons and ions to the highest…
The spectra fits to a sample of 34 supernova remnants (Zeng et al., 2019) are updated. $\gamma$-ray spectra of 20 supernova remnants (SNRs) with a soft TeV spectrum are further analyzed. We found that 17 of them can be fitted in the…
In this paper we investigate the effect of stochasticity in the spatial and temporal distribution of supernova remnants on the spectrum and chemical composition of cosmic rays observed at Earth. The calculations are carried out for…
A giant radio halo (RH) is a diffuse synchrotron emission observed on the scale of megaparsecs (Mpc), typically found in the central region of merging galaxy clusters. Its large size and steep spectrum suggest that it originates from the…
Observations of very-high-energy (VHE) gamma-ray emission from supernova remnants (SNR) established them as sources of accelerated particles up to energies of 100 TeV. The dominant process - leptonic or hadronic - responsible for the VHE…
The origin of Galactic cosmic rays (CR) is still a matter of debate. Diffusive shock acceleration (DSA) applied to supernova remnant (SNR) shocks provides the most reliable explanation. However, within the current understanding of DSA…