Related papers: Low energy cosmic rays
We study the change in cosmic-ray pressure, the change in cosmic-ray density, and the level of cosmic-ray induced heating via Alfven-wave damping when cosmic rays move from a hot ionized plasma to a cool cloud embedded in that plasma. The…
The chemistry of shielded molecular gas is primarily driven by energetic, charged particles dubbed cosmic rays (CRs), in particular those with energies under 1 GeV. CRs ionize molecular hydrogen and helium, the latter of which contributes…
Astrospheres and wind bubbles of massive stars are believed to be sources of cosmic rays with energies $E\lesssim 1\,$TeV. These particles are not directly detectable, but their impact on surrounding matter, in particular ionisation of…
Stars and planets form within cold, dark molecular clouds. In these dense regions, where starlight cannot penetrate, cosmic rays (CRs) are the dominant source of ionization -- driving interstellar chemistry(Dalgarno (2006, PNAS, 103,…
Accelerated particles are ubiquitous in the Cosmos and play a fundamental role in many processes governing the evolution of the Universe at all scales, from the sub-AU ones relevant for the formation and evolution of stars and planets to…
Molecular clouds interacting with supernova remnants may be subject to a greatly enhanced irradiation by cosmic rays produced at the shocked interface between the ejecta and the molecular gas. Over the past decade, broad-band observations…
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…
Continuum gamma-ray emission produced by interactions of cosmic rays with interstellar matter and radiation fields is a probe of non-thermal particle populations in galaxies. After decades of continuous improvements in experimental…
Recent observations of high ionization rates of molecular hydrogen in diffuse interstellar clouds point to a distinct low-energy cosmic-ray component. Supposing that this component is made of nuclei, two models for the origin of such…
Galactic cosmic rays are believed to be generated by diffusive shock acceleration processes in Supernova Remnants, and the arrival direction is likely determined by the distribution of their sources throughout the Galaxy, in particular by…
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…
Dissociation of molecular hydrogen by secondary electrons produced by cosmic ray or X-ray ionization plays a crucial role in the chemistry of the densest part of molecular clouds. Here we study the effect of the mean kinetic energy of…
Several phenomena in high energy astrophysics have been recently related to clusters of galaxies and to cosmic ray interactions occurring inside these structures. In many of these phenomena the observable effects depend on the energy…
The main signature of the interaction between cosmic rays and molecular clouds is the high ionisation degree. This decreases towards the densest parts of a cloud, where star formation is expected, because of energy losses and magnetic…
In the past decade, there has been a significant shift in astrochemistry with a renewed focus on the role of non-thermal processes on the molecular interstellar medium, in particular energetic particles (such as cosmic ray particles and…
New evidence that cosmic rays (hadronic component) are accelerated by supernova remnant shocks all the way from low energies to high energies, has come from recent works combining gamma-ray observations in the sub-GeV to TeV domain on the…
The intergalactic medium - the cosmic gas that fills the great spaces between the galaxies - is affected by processes ranging from quantum fluctuations in the very early universe to radiative emission from newly-formed stars. This gives the…
Cosmic rays (CRs) at sub-TeV energies play a fundamental role in the chemical and dynamical evolution of molecular clouds, as they control the ionisation, dissociation, and excitation of H$_{2}$. Their characterisation is important both for…
It was recently discovered that in some regions of the Galaxy, the cosmic ray (CR) abundance is several orders of magnitude higher than previously thought. Additionally, there is evidence that in molecular cloud envelopes, the CR ionization…
Understanding the interstellar chemistry in low-metallicity environments is crucial to unveil physical and chemical processes in the past Galaxy or those in high-redshift galaxies, where the metallicity was significantly lower compared to…