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Related papers: Diffusive Versus Free-Streaming Cosmic Ray Transpo…

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Galactic cosmic rays (CR) are particles presumably accelerated in supernova remnant shocks that propagate in the interstellar medium up to the densest parts of molecular clouds, losing energy and their ionisation efficiency because of the…

High Energy Astrophysical Phenomena · Physics 2016-05-25 M. Padovani , A. Marcowith , P. Hennebelle , K. Ferrière

The interstellar medium (ISM) of star-forming galaxies is magnetized and turbulent. Cosmic rays (CRs) propagate through it, and those with energies from $\sim\,\rm{GeV} - \rm{TeV}$ are likely subject to the streaming instability, whereby…

Astrophysics of Galaxies · Physics 2022-08-09 James R. Beattie , Mark R. Krumholz , Christoph Federrath , Matt Sampson , Roland M. Crocker

A fairly uniform cosmic-ray (CR) distribution is observed near the Sun, except in the nearby Eridu cloud, which shows an unexplained 30-50% deficit in GeV to TeV CR flux. To explore the origin of this deficit, we studied the Reticulum…

High Energy Astrophysical Phenomena · Physics 2024-03-06 F. R. Kamal Youssef , Isabelle A. Grenier

We introduce a static toy model of the cosmic ray (CR) universe in which cosmic ray propagation is taken to be diffusive and cosmic ray sources are distributed randomly with a density the same as that of local L* galaxies, $5 \times…

Astrophysics · Physics 2007-10-29 Roger Clay , Roland M. Crocker

We show that the well-known discrepancy between the radial dependence of the Galactic cosmic ray (CR) nucleon distribution, as inferred most recently from EGRET observations of diffuse gamma-rays above 100 MeV, and of the most likely CR…

Astrophysics · Physics 2009-11-07 D. Breitschwerdt , V. A. Dogiel , H. J. Voelk

We investigate a mechanism for accelerating cool (10$^4$ K) clouds in the circumgalactic medium (CGM) with cosmic rays (CRs), possibly explaining some characteristics of observed high velocity clouds (HVCs). Enforcing CRs to stream down…

Astrophysics of Galaxies · Physics 2019-07-31 Joshua Wiener , Ellen G. Zweibel , Mateusz Ruszkowski

We discuss the potentials of several experimental configurations dedicated to direct measurements of charged cosmic ray (CR) nuclei at energies $\gsim$ 100 GeV/n. Within a two-zone propagation model for stable CRs, we calculate light…

Astrophysics · Physics 2009-11-10 A. Castellina , F. Donato

We explore the impact of diffusive cosmic rays (CRs) on the evolution of the interstellar medium (ISM) under varying assumptions of supernova explosion environment. In practice, we systematically vary the relative fractions of supernovae…

Astrophysics of Galaxies · Physics 2022-12-28 Christine M. Simpson , Rüdiger Pakmor , Christoph Pfrommer , Simon C. O. Glover , Rowan Smith

The AMS Collaboration has recently released precision data on cosmic ray (CR) leptons and protons at high energies. Interesting progresses have also been made on the measurement of CR nuclei, such as the boron-to-carbon ratio or the lithium…

High Energy Astrophysical Phenomena · Physics 2015-11-02 Nicola Tomassetti

Determining the spatial distribution of Galactic cosmic rays (CRs) is fundamental to understand how these particles propagate in interstellar space and to infer their source spectra. The most sensitive method of studying this problem is…

High Energy Astrophysical Phenomena · Physics 2025-09-26 Paolo Lipari , Silvia Vernetto

We study the effects of escaping cosmic rays (CRs) on the interstellar medium (ISM) around their source with spherically symmetric CR-hydrodynamical simulations taking into account the evolution of the CR energy spectrum, radiative cooling,…

High Energy Astrophysical Phenomena · Physics 2026-04-07 Jiro Shimoda , Katsuaki Asano , Shu-ichiro Inutsuka

Chemistry in diffuse molecular clouds relies primarily on rapid ion-molecule reactions. Formation of the initial ions, H$^+$ and H$_2^+$, is dominated by cosmic-ray ionization of H and H$_2$, making the cosmic-ray ionization rate (denoted…

Observations of the emission of the carbon cycle species (C, C+ CO) are commonly used to diagnose gas properties in the interstellar medium but are significantly sensitive to the cosmic-ray ionization rate. The carbon-cycle chemistry is…

Astrophysics of Galaxies · Physics 2022-03-14 Brandt A. L. Gaches , Thomas G. Bisbas , Shmuel Bialy

Acceleration of cosmic-ray electrons (CRe) in the intra-cluster-medium (ICM) is probed by radio observations that detect diffuse, Mpc-scale, synchrotron sources in a fraction of galaxy clusters. Giant radio halos are the most spectacular…

High Energy Astrophysical Phenomena · Physics 2015-09-11 G. Brunetti

Cosmic rays (CRs) are a pivotal non-thermal component of galaxy formation and evolution. However, the intricacies of CR physics, particularly how they propagate in the circumgalactic medium (CGM), remain largely unconstrained. In this work,…

Cosmic rays are the only agent able to penetrate into the interior of dense molecular clouds. Depositing (part of) their energy through ionisation, cosmic rays play an essential role in determining the physical and chemical evolution of…

High Energy Astrophysical Phenomena · Physics 2023-06-21 Vo Hong Minh Phan , Sarah Recchia , Philipp Mertsch , Stefano Gabici

Cosmic-ray (CR) diffusion is the result of the interaction of such charged particles against magnetic fluctuations. These fluctuations originate from large-scale turbulence cascading towards smaller spatial scales, decomposed into three…

High Energy Astrophysical Phenomena · Physics 2022-11-30 Ottavio Fornieri , Heshou Zhang

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…

High Energy Astrophysical Phenomena · Physics 2020-10-21 Kedron Silsbee , Alexei V. Ivlev

Supernova remnants are believed to be the main sources of galactic Cosmic Rays (CR). Within this framework, particles are accelerated at supernova remnant shocks and then released in the interstellar medium. The mechanism through which CRs…

High Energy Astrophysical Phenomena · Physics 2016-08-19 Lara Nava , Stefano Gabici , Alexandre Marcowith , Giovanni Morlino , Vladimir S. Ptuskin

Cosmic ray propagation in the Galaxy is shortly reviewed. In particular we consider the self-consistent models of CR propagation. In these models CR streaming instability driven by CR anisotropy results in the Alfv\'enic turbulence which in…

High Energy Astrophysical Phenomena · Physics 2015-06-23 V. N. Zirakashvili