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We study the propagation of cosmic rays (CRs) through a simulation of magnetohydrodynamic (MHD) turbulence at unprecedented resolution of $10{,}240^3$. We drive turbulence that is subsonic and super-Alfv\'enic, characterized by $\delta…

The origin of cosmic rays (CRs) has puzzled scientists since the pioneering discovery by Victor Hess in 1912. In the last decade, however, modern supercomputers have opened a new window on the processes regulating astrophysical…

High Energy Astrophysical Phenomena · Physics 2015-11-27 Damiano Caprioli

The spatial distribution of cosmic ray (CR) particles in the interstellar medium (ISM) is of major importance in radio astronomy, where its knowledge is essential for the interpretation of observations, and in theoretical astrophysics,…

Astrophysics of Galaxies · Physics 2023-06-28 Devika Tharakkal , Andrew P. Snodin , Graeme R. Sarson , Anvar Shukurov

The majority of galactic baryons reside outside of the galactic disk in the diffuse gas known as the circumgalactic medium (CGM). While state-of-the art simulations excel at reproducing galactic disk properties, many struggle to drive…

Astrophysics of Galaxies · Physics 2018-12-05 Iryna Butsky , Thomas R. Quinn

Galaxies with high star-formation rate surface densities often host large-scale outflows that redistribute energy, momentum, and baryons between the interstellar medium and the halo, making them a key feedback channel regulating galaxy…

Astrophysics of Galaxies · Physics 2025-09-23 Ellis R. Owen , Leonard E. C. Romano , Kentaro Nagamine

Astrophysical plasmas are turbulent and magnetized. The interaction between cosmic rays (CRs) and magnetohydrodynamic (MHD) turbulence is a fundamental astrophysical process. Based on the current understanding of MHD turbulence, we revisit…

High Energy Astrophysical Phenomena · Physics 2020-05-13 Siyao Xu , Alex Lazarian

We investigate the production of cosmic ray (CR) protons at cosmological shocks by performing, for the first time, numerical simulations of large scale structure formation that include directly the acceleration, transport and energy losses…

Astrophysics · Physics 2009-11-06 Francesco Miniati , Dongsu Ryu , Hyesung Kang , T. W. Jones

Understanding cosmic ray (CR) diffusion in a partially ionized medium is both crucial and challenging. In this study, we investigate CR perpendicular superdiffusion and parallel transport in turbulent, partially ionized media using…

Astrophysics of Galaxies · Physics 2025-10-09 Yue Hu , Siyao Xu , Alex Lazarian , James M. Stone , Philip F. Hopkins

The majority of cosmic rays (CRs) generated by star-forming galaxies escape them and enter the intergalactic medium (IGM). Galactic wind termination shocks might also accelerate CRs. I show that the mean pressure of these CRs can reach to…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Brian C. Lacki

The cosmic ray current-driven (CRCD) instability, predicted by Bell (2004), consists of non-resonant, growing plasma waves driven by the electric current of cosmic rays (CRs) that stream along the magnetic field ahead of both relativistic…

Astrophysics · Physics 2011-02-11 Mario A. Riquelme , Anatoly Spitkovsky

We conduct global galactic--scale magnetohydrodynamical (MHD) simulations of the cosmic--ray driven dynamo. We assume that exploding stars deposit small--scale, randomly oriented, dipolar magnetic fields into the differentially rotating…

Astrophysics of Galaxies · Physics 2009-11-13 Michał Hanasz , Dominik Wóltański , Kacper Kowalik , Rafał Pawłaszek

Recent efforts in cosmic ray (CR) confinement and transport theory are discussed. Three problems are addressed as being crucial for understanding the present day observations and their possible telltale signs of the CR origin. The first…

High Energy Astrophysical Phenomena · Physics 2016-10-11 M. A. Malkov

Galaxy formation simulations demonstrate that cosmic-ray (CR) feedback may be important in the launching of galactic-scale winds. CR protons dominate the bulk of the CR population, yet most observational constraints of CR feedback come from…

High Energy Astrophysical Phenomena · Physics 2018-11-07 Laura A. Lopez , Katie Auchettl , Tim Linden , Alberto D. Bolatto , Todd A. Thompson , Enrico Ramirez-Ruiz

We present semi-analytical models of galactic outflows in high redshift galaxies driven by both hot thermal gas and non-thermal cosmic rays. Thermal pressure alone may not sustain a large scale outflow in low mass galaxies (i.e $M\sim…

Astrophysics of Galaxies · Physics 2018-02-21 Saumyadip Samui , Kandaswamy Subramanian , Raghunathan Srianand

We investigate the transport of spectrally resolved cosmic ray (CR) protons with kinetic energies between $1-100$ GeV within the dynamic, multiphase interstellar medium (ISM), using a two-moment CR fluid solver applied to a TIGRESS MHD…

High Energy Astrophysical Phenomena · Physics 2025-07-02 Lucia Armillotta , Eve C. Ostriker , Nora B. Linzer

The propagation of TeV-PeV cosmic rays (CR) in our Galaxy can be described as a diffusive process. We discuss here two effects, with important observational consequences, that cannot be predicted by the diffusion approximation in its usual…

High Energy Astrophysical Phenomena · Physics 2014-12-01 G. Giacinti

Active galactic nuclei (AGN) provide energetic feedback necessary to `turn off' star formation in high-mass galaxies (M$_{\rm halo} \geq $ 10$^{12.5}$ M$_{\odot}$, $10.4 \leq \log(\frac{M_*}{M_\odot}) \leq 11$) as observed. Cosmic rays…

Astrophysics of Galaxies · Physics 2026-04-14 Charvi Goyal , Sam B. Ponnada , Philip F. Hopkins , Sarah Wellons , Jose A. Benavides , Kung-Yi Su

Multichannel Cosmic Ray (CR) spectra and the large scale CR anisotropy can hardly be made compatible in the framework of conventional isotropic and homogeneous propagation models. These models also have problems explaining the longitude…

High Energy Astrophysical Phenomena · Physics 2012-06-13 Carmelo Evoli , Daniele Gaggero , Dario Grasso , Luca Maccione

The spectrum of cosmic rays (CRs) is affected by their escape from an acceleration site. This may have been observed not only in the gamma-ray spectrum of young supernova remnants (SNRs) such as RX J1713.7-3946, but also in the spectrum of…

High Energy Astrophysical Phenomena · Physics 2015-05-14 Yutaka Ohira , Kohta Murase , Ryo Yamazaki

Galactic winds constitute a primary feedback process in the ecology and evolution of galaxies. They are ubiquitously observed and exhibit a rich phenomenology, whose origin is actively investigated both theoretically and observationally.…

High Energy Astrophysical Phenomena · Physics 2022-07-13 Sarah Recchia