Related papers: PeV Cosmic Rays: A Window on the Leptonic Era?
The observed interaction energy of cosmic rays with atmospheric nuclei reaches up to a PeV in the center of mass. We compute nucleon-nucleon and nucleon-neutrino cross sections for various generic parton cross sections appearing in string…
Recent observations show that the cosmic ray nuclei spectra start to harden above 100 GeV, in contradiction with the conventional steady-state cosmic ray model. We had suggested that this anomaly is due to the propagation effect of cosmic…
The stellar binary $\eta$ Carinae has been observed during its full orbital period in gamma rays by the Fermi-Large Area Telescope (LAT). The shock-accelerated electrons in the colliding winds of the two stars radiate synchrotron photons in…
Observations of the Milky Way at TeV-PeV energies reveal a bright diffuse flux of hadronic cosmic rays and also bright point sources of gamma rays. If the gamma-ray sources are hadronic cosmic-ray accelerators, then they must also be…
The possibility for a self-consistent description of all the basic features of the observed cosmic ray spectra and primary composition variations in the energy range of $10^{15}\div 10^{20}$ eV within the Galactic origin scenario is…
In this report we review the important progress made in recent years towards understanding the experimental data on ultra-high-energy ($E \gtrsim 10^9$ GeV) cosmic rays. We begin with a general survey of the available data, including a…
Cosmic rays around the knee are generally believed to be of galactic origin. Observations on their energy spectrum and chemical composition are important for understanding the acceleration and propagation of these cosmic rays. In addition,…
Observations of cosmic rays with energies above ~ 4 x 10^{10} GeV have inspired several speculative suggestions concerning their origin. The crucial question is whether or not the spectrum exhibits the expected `GZK cutoff' at this energy…
The energy spectrum of cosmic neutrinos, which was recently reported by the IceCube collaboration, shows a gap between 400 TeV and 1 PeV. An unknown neutrino interaction mediated by a field with a mass of the MeV scale is one of the…
The luminosity densities of high-energy cosmic radiations are studied to find connections among the various components, including high-energy neutrinos measured with IceCube and gamma rays with the Fermi satellite. Matching the cosmic-ray…
Using the concept developed in earlier papers, that the cosmic rays originate in three different main sites, a) the normal supernova explosions into the interstellar medium, b) the supernova explosions into a stellar wind, and c) powerful…
Accretion and merger shocks in clusters of galaxies are potential accelerators of high-energy protons, which can give rise to high-energy neutrinos through pp interactions with the intracluster gas. We discuss the possibility that protons…
Heavy neutrinos with masses in the MeV range can in principle simultaneously explain the light neutrino masses and the origin of baryonic matter in the universe. The strongest constraints on their properties come from their potential impact…
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…
Recent measurements of PeV energy neutrinos at IceCube and a 3.5 keV X-ray line in the spectra of several galaxies are both tantalizing signatures of new physics. This paper shows that one or both of these observations can be explained…
We report, for the first time, the long-awaited detection of diffuse gamma rays with energies between 100 TeV and 1 PeV in the Galactic disk. Particularly, all gamma rays above 398 TeV are observed apart from known TeV gamma-ray sources and…
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…
The spectral shape of cosmic ray positrons and antiprotons has been accurately measured in the broad kinetic energy range 1-350 GeV. In the higher part of this range (E > 30 GeV) the e+ and pbar are both well described by power laws with…
More than 90% of the Galactic gas-related gamma-ray emissivity above 1 GeV is attributed to the decay of neutral pions formed in collisions between cosmic rays and interstellar matter, with lepton-induced processes becoming increasingly…
The spectral hardenings of cosmic ray nuclei above $\sim 200$ GV followed by softenings around 10 TV, the knee of the all-particle spectrum around PeV energies, as well as the pattern change of the amplitude and phase of the large-scale…