Related papers: The Interaction of Cosmic Rays with Diffuse Clouds
The absence of large cooling flows in cool core clusters appears to require self-regulated energy feedback by active galactic nuclei (AGNs) but the exact heating mechanism has not yet been identified. Here, we analyse whether a combination…
The cosmic-ray flux in the Galaxy can be characterized by combining the knowledge of the distribution of gas in the Galaxy and the observation of gamma rays. We analyze the data from the HAWC Observatory to look for gamma rays in three…
Cosmic rays (CRs) generate diffuse emission while interacting with the Galactic magnetic field (B-field), the interstellar gas and the radiation field. This diffuse emission extends from radio, microwaves, through X-rays, to high-energy…
Low-energy cosmic rays are the dominant source of ionization for molecular cloud cores. The ionization fraction, in turn, controls the coupling of the magnetic field to the gas and hence the dynamical evolution of the cores. The purpose of…
Molecular clouds are expected to emit non-thermal radiation due to cosmic ray interactions in the dense magnetized gas. Such emission is amplified if a cloud is located close to an accelerator of cosmic rays and if cosmic rays can leave the…
Among the most puzzling questions in climate change is that of solar-climate variability, which has attracted the attention of scientists for more than two centuries. Until recently, even the existence of solar-climate variability has been…
Low-energy cosmic rays, in particular protons with energies below 1 GeV, are significant drivers of the thermochemistry of molecular clouds. However, these cosmic rays are also greatly impacted by energy losses and magnetic field transport…
We perform zoom-in cosmological simulations of a suite of dwarf galaxies, examining the impact of cosmic-rays generated by supernovae, including the effect of diffusion. We first look at the effect of varying the uncertain cosmic ray…
We review some of the recent progress in our knowledge about high-energy cosmic rays, with an emphasis on the interpretation of the different observational results. We discuss the effects that are relevant to shape the cosmic ray spectrum…
A field with particularly exciting results over the past few years is the study of the interaction of cosmic rays with interstellar matter. For star formation to take place, gas and dust need to be sufficiently cold for gravity to overcome…
In addition to lines originating in a soft phase at ~0.8 keV and to cold molecular clouds, the X-ray spectra from the Galactic center region also exhibit properties similar to those of a diffuse, thin, very hot plasma at 8 keV on a scale of…
A significant correlation between the annual cosmic ray flux and the amount of low clouds has recently been found for the past 20 years. However, of the physical explanations suggested, none has been quantitatively verified in the…
Cosmic rays generated by supernovae carry away a significant portion of the lifetime energy emission of their parent star, making them a plausible mechanism for heating the early universe intergalactic medium (IGM). Following a review of…
Observations of non-thermal emission from several supernova remnants suggest that magnetic fields close to the blastwave are much stronger than would be naively expected from simple shock compression of the field permeating the interstellar…
More and more observations have indicated the existence of slow diffusion phenomena in astrophysical environments, such as around the supernova remnants and pulsar $\gamma$-ray halos, where the diffusion coefficient of cosmic rays (CRs)…
A common situation in galactic and intergalactic gas involves cold dense gas in motion relative to hot diffuse gas. Kelvin-Helmholtz instability creates a turbulent mixing layer and populates the intermediate-temperature phase, which often…
The analytical theory of diffusive cosmic ray acceleration at parallel stationary shock waves with magnetostatic turbulence is generalized to arbitrary shock speeds $V_s=\beta_1c$, including in particular relativistic speeds. This is…
Galactic diffuse gamma-ray emission is produced by the interaction of high-energy cosmic rays propagating through the Milky Way with interstellar gas and radiation fields. Its measurement can provide crucial insights into the acceleration…
In this article, momentum transport generated by the combined effects of pitch-angle diffusion and Background Flow Velocity Inhomogeneities (BFVIs) is proposed to obtain a cosmic rays acceleration mechanism, starting from the well-known…
Cosmic rays are crucial for the chemistry of molecular clouds and their evolution. They provide essential ionizations, dissociations, heating and energy to the cold, dense cores. As cosmic rays pierce through the clouds they are attenuated…