Related papers: Energetic Particles of Cosmic Accelerators I: Gala…
High-energy cosmic rays can be accelerated in clusters of galaxies, by mega-parsec scale shocks induced by accretion of gas during the formation of large-scale structure, or by powerful sources harbored in clusters. Once accelerated, the…
The origin of cosmic rays is one of the major unresolved questions in astrophysics. In particular, the highest energy cosmic rays observed possess macroscopic energies and their origin is likely associated with the most energetic processes…
Our Galaxy is the largest nuclear interaction experiment which we know, because of the interaction between cosmic ray particles and the interstellar material. Cosmic rays are particles, which have been accelerated in the Galaxy or in…
Cosmic-rays with energies exceeding 10^{19} eV are referred to as Ultra High Energy Cosmic Rays (UHECRs). The sources of these particles and their acceleration mechanism are unknown, and for many years have been the issue of much debate.…
The nonthermal characteristics of starburst galaxies and galaxy clusters are reviewed and the perspectives for their observation in high energy gamma rays discussed. It is argued that starburst galaxies should have physically similar and…
Recent international efforts have brought us closer to unveiling the century old mystery of the origin of cosmic rays. Cosmic ray, gamma ray, and neutrino observatories are reaching the necessary sensitivity to study the highest energy…
The existence of cosmic rays of energies exceeding 10^20 eV is one of the mysteries of high energy astrophysics. The spectrum and the high energy to which it extends rule out almost all suggested source models. The challenges posed by…
This is a summary of a series of lectures on the current experimental and theoretical status of our understanding of origin and nature of cosmic radiation. Specific focus is put on ultra-high energy cosmic radiation above ~10^17 eV,…
The article gives a brief overview, aimed at nonspecialists, about the goals and selected recent results of the detection of very-high energy gamma-rays (energies above 100 GeV) with ground based detectors. The stress is on the physics…
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…
The origin of Galactic cosmic rays (with energies up to 10^15 eV) remains unclear, though it is widely believed that they originate in the shock waves of expanding supernova remnants. Currently the best way to investigate their acceleration…
After a brief review of galactic cosmic rays in the GeV to TeV energy range, we describe some current problems of interest for particles of very high energy. Particularly interesting are two features of the spectrum, the `knee' above…
Cosmic rays are energetic nuclei that permeate the entire Galactic disk. Their existence requires the presence of powerful particle accelerators. While Galactic supernova explosions may supply the required energy, there is growing evidence…
Simple arguments concerning power and acceleration efficiency show that ultra-high energy cosmic rays (UHECRS) with energies >~ 10^{19} eV could originate from GRBs. Neutrons formed through photo-pion production processes in GRB blast waves…
Very-high energy (GeV-TeV) gamma rays in the universe suggest the presence of an accelerator in the source. Neutrinos and gamma rays are intriguing astrophysical messengers. Multi-messenger particle emission produced by interactions of…
The particle and radiation environment in cis-lunar space is becoming increasingly important as more hardware and human assets occupy various orbits around the Earth and space exploration efforts turn to the Moon and beyond. Since 2020, the…
I give a synopsis of two aspects of the Galactic Cosmic Ray (GCR) acceleration problem: the importance of the medium energy gamma-ray window, and several specific astrophysical sources which merit further investigation.
Historically cosmic rays have always been at the intersection of astrophysics with particle physics. This is still and especially true in current days where experimenters routinely observe atmospheric showers from particles whose energies…
Ultrarelativistic particles called cosmic rays permeate the Milky Way, propagating through the Galactic turbulent magnetic fields. The mechanisms under which these particles increase their energy can be reasonably described by current…
Massive Star Clusters (SCs) have been proposed as additional contributors to Galactic Cosmic rays (CRs), to overcome the limitations of supernova remnants (SNRs) to reach the highest energy end of the CR spectrum. Thanks to fast mass losses…