相关论文: Interstellar Gamma Ray Lines from Low Energy Cosmi…
Gamma-ray absorption due to gamma-gamma-pair creation on cosmological scales depends on the line-of-sight integral of the evolving density of low-energy photons in the Universe, i.e. on the history of the diffuse, isotropic radiation field.…
The origin of the ultra high energy cosmic rays via annihilation of heavy stable, fermions "f", of the cosmological dark matter (DM) is studied. The particles in question are supposed to be created by the scalaron decays in $R^2$ modified…
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…
Recent results from the Pierre Auger Observatory show energy dependent chemical composition of ultrahigh-energy cosmic rays (UHECR) with a growing fraction of heavy elements at high energies. This points to a non-negligible contribution of…
We re-visit the production of cosmic rays by cusps on cosmic strings. If a scalar field (``Higgs'') has a linear interaction with the string world-sheet, such as would occur if there is a bosonic condensate on the string, cusps on string…
Cosmic rays are a sample of solar, galactic and extragalactic matter. Their origin and properties are one of the most intriguing question in modern astrophysics. The most energetic events and active objects in the Universe: supernovae…
The observed anomalous excess of high-energy cosmic ray (CR) positrons is widely discussed as possible indirect evidence for dark matter (DM). However, any source of cosmic positrons is inevitably the source of gamma radiation. The least…
The luminosities of short gamma ray burst host galaxies are anticorrelated with both the isotropic equivalent gamma ray energy and the gamma ray luminosity of the explosions. Observational selection effects only strengthen the significance…
The high-energy universe has revealed that energetic particles are ubiquitous in the cosmos and play a vital role in the cultivation of cosmic environments on all scales. Energetic particles in our own galaxy, galactic cosmic rays (GCRs),…
Blazars are expected to produce both gamma rays and cosmic rays. Therefore, observed high-energy gamma rays from distant blazars may contain a significant contribution from secondary gamma rays produced along the line of sight by the…
Motivated by the discovery of the ultra-strong emission line starburst galaxies (EELGs) known as "green pea galaxies", we consider here their contribution to the intergalactic flux of ionizing UV at high redshifts. Most galaxies that have…
We discuss some open problems in the understanding of the Early Solar System abundances of short-lived radioactive isotopes, and the important clarification expected on this matter by precise measurements of the average galactic abundances…
Population studies of unidentified EGRET sources suggest that there exist at least three different populations of galactic gamma-ray sources. One of these populations is formed by young objects distributed along the galactic plane with a…
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…
In recent years, many gamma-ray sources have been identified, yet the unresolved component hosts valuable information on the faintest emission. In order to extract it, a cross-correlation with gravitational tracers of matter in the Universe…
The majority of the highest energy cosmic rays are thought to be electrically charged: protons or nuclei. Charged particles experience angular deflections as they pass through galactic and extra-galactic magnetic fields. As a consequence…
In a recent paper, Romero et al. (1999) have presented the results of a positional correlation analysis of the low-latitude unidentified gamma-ray sources in the Third EGRET catalog with complete lists of galactic objects like supernova…
Very recently, it was pointed out that there exists a population of gamma-ray sources without associations at other wavelengths which exhibit spectral features consistent with mono-energetic lines at energies of approximately 111 and 129…
Cosmic rays travel throughout the Galaxy, leaving traces from radio to ultra-high-energy gamma rays due to interactions with the interstellar gas, radiation field and magnetic field. Therefore, it is necessary to utilize multi-wavelength…
A number of signals involving charged cosmic rays and high-energy photons have been interpreted as being due to annihilating dark matter. This article provides an overview of the experimental evidence and discusses in particular detections…