Related papers: Cosmic Ray Origin and Propagation Model
Galactic cosmic rays are believed to be accelerated at supernova remnant shocks. Though very popular and robust, this conjecture still needs a conclusive proof. The strongest support to this idea is probably the fact that supernova remnants…
Cosmic rays are charged energetic particles that permeate the interstellar medium. Their sizeable energy share and penetration power makes them essential players in the dynamical and chemical processes that rule Galactic evolution, such as…
The origin of cosmic rays is one of the major unresolved astrophysical questions. In particular, the highest energy cosmic rays observed possess macroscopic energies and their origin is likely to be associated with the most energetic…
A review is given of the main properties of the charged component of galactic cosmic rays, particles detected at Earth with an energy spanning from tens of MeV up to about 10^19 eV. After a short introduction to the topic and an historical…
The origin of cosmic rays in our Galaxy remains a subject of active debate. While supernova remnant shocks are often invoked as the sites of acceleration, it is now widely accepted that the difficulties of such sources in reaching PeV…
The diffusive paradigm for the transport of Galactic cosmic rays is central to our understanding of the origin of these high energy particles. However, it is worth recalling that the normalization, energy dependence, and spatial extent of…
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…
We consider a cosmic ray spectrum that is a power law in momentum down to a cutoff and derive a lower cutoff corresponding to $E_{kin} \sim (30-60)$ MeV from the observed ionization rates in nearby diffuse clouds. While the real spectra of…
We introduce neutrino astronomy from the observational fact that Nature accelerates protons and photons to energies in excess of 10^{20} and 10^{13} eV, respectively. Although the discovery of cosmic rays dates back close to a century, we…
Galactic cosmic-rays (GCRs) are thought to be accelerated in strong shocks induced by massive star winds and supernova explosions sweeping across the interstellar medium. But the phase of the interstellar medium from which the CRs are…
We derive observational consequences of the hypothesis that cosmic rays (CR's) of energy $>10^{19}eV$ originate in the same cosmological objects producing gamma-ray bursts (GRB's). Inter-galactic magnetic fields $\gtrsim 10^{-12} G$ are…
Physicists have pondered the origin of cosmic rays for over a hundred years. However the last few years have seen an upsurge in the observation, progress in the theory and a genuine increase in the importance attached to the topic due to…
The origin of galactic cosmic rays is one of the most interesting unsolved problems in astroparticle physics. Experimentally, the problem is attacked by a multi-disciplinary effort, namely by direct measurements of cosmic rays above the…
The bulk of observed ultrahigh energy cosmic rays could be light or heavier elements, and originate from an either steady or transient population of sources. This leaves us with four general categories of sources. Energetic requirements set…
The diffuse galactic gamma-ray spectrum measured by the EGRET experiment \citep{Hunter:1997} are interpreted within a scenario in which cosmic rays (CRs) are injected by three different kind of sources, (i) supernovae (SN) which explode…
Cosmic rays at the Earth include a secondary component originating in collisions of primary particles with the diffuse interstellar gas. The secondary cosmic rays are relatively rare but carry important information on the Galactic…
In this chapter I give an overview of shock acceleration, including a discussion of the maximum energies possible and the shape of the spectrum near cut-off, interactions of high energy cosmic rays with, and propagation through, the…
The origin of the bulk of cosmic rays (CRs) observed at Earth is the topic of a century long investigation, paved with successes and failures. From the energetic point of view, supernova remnants (SNRs) remain the most plausible sources of…
Recently, two nearby prominent starburst galaxies, M82 and NGC253, have been detected as point-like sources with gamma-ray telescopes at TeV energies [1] [2]. It has been claimed that these detections show that the cosmic ray intensity in…
From the analysis of the flux of high energy particles, $E>3\cdot 10^{18}eV$, it is shown that the distribution of the power density of extragalactic rays over energy is of the power law, ${\bar q}(E)\propto E^{-2.7}$, with the same index…