相关论文: Low-Energy Cosmic Rays and Associated MeV Gamma-Ra…
Latest precise cosmic-ray (CR) measurements and present gamma-ray observations have started challenging our understanding of CR transport and interaction in the Galaxy. Moreover, because the density of CRs is similar to the density of the…
Low-energy cosmic rays (LECRs) contribute substantially to the energy balance of the interstellar medium. They play also significant role in the heating and chemistry of gas, and, consequently, on the star formation process. Because of the…
In recent years, exciting developments have taken place in the identification of the role of cosmic rays in star-forming environments. Observations from radio to infrared wavelengths and theoretical modelling have shown that low-energy…
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…
Fermi/LAT observations of star-forming galaxies in the ~0.1-100GeV range have made possible a first population study. Evidence was found for a correlation between gamma-ray luminosity and tracers of the star formation activity. Studying…
Solar flare observations are used to demonstrate the new technique of abundance determination based on gamma ray line emission produced by accelerated particle bombardment. Some of the implications of similar gamma ray line emission…
Measurements of the low energy spectrum of Galactic Cosmic Rays (GCR) by detectors at or near the Earth are affected by Solar modulation. To overcome this difficulty, we consider nearby molecular clouds as GCR detectors outside the Solar…
Cosmic rays may have contributed to the start of life on Earth. Here, we investigate the evolution of the Galactic cosmic ray spectrum at Earth from ages $t = 0.6-6.0\,$Gyr. We use a 1D cosmic ray transport model and a 1.5D stellar wind…
Cosmic rays of kinetic energies below ~1 GeV per nucleon are thought to play a key role in the chemistry and dynamics of the interstellar medium. They are also thought to be responsible for nucleosynthesis of the light elements Li, Be, and…
Ultra High Energy Cosmic Rays (UHECRs) interact en route to Earth, producing secondary gamma-rays. For the case of high cosmic ray power and weak intergalactic magnetic fields, the deflections of these UHECRs may be small leading to…
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),…
Low-energy cosmic rays (LECRs) dominate the ionization in dense regions of molecular clouds in which other ionizers such as UV or X-ray photons are effectively shielded. Thus it was argued that the high ionization rate at the central…
Diffuse gamma-ray emission is a key tracer of cosmic rays (CRs) in galaxies, encoding information about their transport, energetics, and interactions with the interstellar medium. Interpreting the Milky Way gamma-ray sky is challenging…
Feedback from low-excitation radio galaxies (LERGs) plays a key role in the lifecycle of massive galaxies in the local Universe; their evolution, and the impact of these active galactic nuclei on early galaxy evolution, however, remain…
We address the role of gamma-ray astronomy in the investigation of nonthermal processes in the large scale structure of the universe. Based on EGRET upper limits on nearby galaxy clusters (GCs) we constrain the acceleration efficiency of CR…
The Fermi Large Area Telescope (Fermi LAT) collaboration has recently reported on 50 months of measurements of the isotropic Extragalactic Gamma Ray Background (EGRB) spectrum between $100\mbox{MeV}$ and $820\mbox{GeV}$. Ultrahigh Energy…
Cosmic rays (CRs) are charged particles that arrive at Earth isotropically from all directions and interact with the atmosphere. The presence of a spectral knee feature seen in the CR spectrum at $\sim$3 PeV energies is an evidence that…
Low energy cosmic rays (up to the GeV energy domain) play a crucial role in the physics and chemistry of the densest phase of the interstellar medium. Unlike interstellar ionising radiation, they can penetrate large column densities of gas,…
Cosmic rays can interact with the solar atmosphere and produce a slew of secondary messengers, making the Sun a bright gamma-ray source in the sky. Detailed observations with Fermi-LAT have shown that these interactions must be strongly…
Evidence for the existence of low energy cosmic rays in the Galaxy comes from the COMPTEL observations of gamma ray line emission from Orion, and also from light element abundance data which seem to suggest a low energy rather than a…