Related papers: Nonthermal processes and particle acceleration in …
It is thought that Galactic cosmic ray (CR) nuclei are gradually accelerated to high energies (up to ~300 TeV/nucleon, where 1TeV=10^12eV) in the expanding shock-waves connected with the remnants of powerful supernova explosions. However,…
The recent HESS detections of supernova remnant shells in TeV gamma-rays confirm the theoretical predictions that supernova remnants can operate as powerful cosmic ray accelerators. If these objects are responsible for the bulk of galactic…
Supernova remnants are often presented as the most probable sources of Galactic cosmic rays. This idea is supported by the accumulation of evidence that particle acceleration is happening at supernova remnant shocks. Observations in the TeV…
We simulate time-dependent particle acceleration in the blast wave of a young supernova remnant (SNR), using a Monte Carlo approach for the diffusion and acceleration of the particles, coupled to an MHD code. We calculate the distribution…
To better model the efficient production of cosmic rays (CRs) in supernova remnants (SNRs) with the associated coupling between CR production and SNR dynamics, we have generalized an existing cr-hydro-NEI code (i.e., Ellison et al. 2012) to…
Cosmological hydrodynamic simulations have demonstrated that shock waves could be produced in the intergalactic medium by supersonic flow motions during the course of hierarchical clustering of the large-scale-structure in the Universe.…
Recent gamma-ray observations show that middle aged supernova remnants (SNRs) interacting with molecular clouds (MCs) can be sources of both GeV and TeV emission. Based on the MC association, two scenarios have been proposed to explain the…
Supernova remnants are believed to be the main sources of galactic Cosmic Rays (CR). Within this framework, particles are accelerated at supernova remnant shocks and then released in the interstellar medium. The mechanism through which CRs…
Identifying the accelerators of Galactic cosmic ray protons (CRs) with energies up to a few PeV ($10^{15}$ eV) remains a theoretical and observational challenge. Supernova remnants (SNRs) represent strong candidates, as they provide…
Context. Supernova remnants (SNRs) are thought to be the main source of Galactic cosmic rays (CRs) up to the "knee" in CR spectrum. During the evolution of a SNR, the bulk of the CRs are confined inside the SNR shell. The highest-energy…
Supernova explosions into predecessor stellar winds can lead to particle acceleration, which we suggest can explain most of the observed cosmic rays of the nuclei of Helium and heavier elements, from GeV in particle energies up to near $3…
When a supernova remnant (SNR) interacts with the dense material of an interstellar cloud, its shock wave decelerates rapidly, and the post-shock temperature drops to levels that permit efficient cooling of the shocked plasma. At this…
SNRs are likely to be significant sources of Galactic cosmic rays up to the knee. They produce gamma rays in the very-high-energy (E>100 GeV) range mainly via two mechanisms: hadronic interactions of accelerated protons with the…
While supernova remnants (SNRs) have long been considered prime candidates as sources of cosmic rays, it is only recently that X-ray observations have identified several shell-type SNRs dominated by nonthermal emission, thus revealing…
Diffusive shock acceleration (DSA) at relativistic shocks is expected to be an important acceleration mechanism in a variety of astrophysical objects including extragalactic jets in active galactic nuclei and gamma ray bursts. These sources…
H-alpha emission from supernova remnants (SNRs) implies the existence of neutral hydrogens in the ambient medium. In the precursor of an SNR shock modified by cosmic rays (CRs), upstream plasmas are pushed by the CR pressure, but neutral…
The spectra of high-energy protons and nuclei accelerated by supernova remnant shocks are calculated taking into account magnetic field amplification and Alfvenic drift both upstream and downstream of the shock for different types of…
Estimating the cosmic-ray acceleration efficiency $ \epsilon $ in supernova remnants (SNRs) through observations is a challenging task in general. Based on the Rankine-Hugoniot shock conditions, we find an anticorrelation between $ \epsilon…
Particle acceleration to suprathermal energies in strong astrophysical shock waves is a widespread phenomenon, generally explained by diffusive shock acceleration. Such shocks can also amplify upstream magnetic field considerably beyond…
Using a semianalytical approach based on the thin-shell approximation, we calculate the long-term evolution of supernova remnants (SNRs) while also accounting for the cosmic rays (CRs) accelerated at their blast waves. Our solution…