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Cosmic rays (CRs) are thought to play an important role in galaxy evolution. We study their effect when coupled to other important sources of feedback, namely supernovae and stellar radiation, by including CR anisotropic diffusion and…

Astrophysics of Galaxies · Physics 2022-05-27 Marion Farcy , Joakim Rosdahl , Yohan Dubois , Jérémy Blaizot , Sergio Martin-Alvarez

The cataclysmic explosions of massive stars as supernovae are one of the key ingredients of galaxy formation. However, their evolution is not well understood in the presence of magnetic fields or cosmic rays (CRs). We study the expansion of…

The $\gamma$-ray emission of star-forming (SF) galaxies is attributed to hadronic interactions of cosmic ray (CR) protons with the interstellar gas and contributions from CR electrons via bremsstrahlung and inverse Compton (IC) scattering.…

High Energy Astrophysical Phenomena · Physics 2021-05-26 Maria Werhahn , Christoph Pfrommer , Philipp Girichidis , Georg Winner

Non-thermal (relativistic) particles are injected into the cosmos by structure formation shock waves, active galactic nuclei and stellar explosions. We present a suite of unigrid cosmological simulations (up to $2048^3$) using a two-fluid…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-05 Franco Vazza , Claudio Gheller , Marcus Brüggen

We present a new code aimed at the simulation of diffusive shock acceleration (DSA), and discuss various test cases which demonstrate its ability to study DSA in its full time-dependent and non-linear developments. We present the numerical…

Astrophysics · Physics 2009-11-13 Gilles Ferrand , Turlough Downes , Alexandre Marcowith

Cosmic rays (CRs) are known to play a key role in many astrophysical environments: they can modify shock dynamics, influence the thermochemistry and the ionization of the interstellar medium, regulate galaxy mass content by driving galactic…

High Energy Astrophysical Phenomena · Physics 2026-02-25 Nimatou-Seydi Diallo , Yohan Dubois , Alexandre Marcowith , Joki Rosdahl , Benoît Commerçon

We reexamine nonlinear diffusive shock acceleration (DSA) at cosmological shocks in the large scale structure of the Universe, incorporating wave-particle interactions that are expected to operate in collisionless shocks. Adopting simple…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Hyesung Kang , Dongsu Ryu

Cosmic rays (CRs) have critical impacts in the multiphase interstellar medium (ISM), driving dynamical motions in low-density plasma and modifying the ionization state, temperature, and chemical composition of higher-density atomic and…

Astrophysics of Galaxies · Physics 2022-02-23 Christopher J. Bambic , Xue-Ning Bai , Eve C. Ostriker

In the interstellar medium of galaxies and the intracluster gas of galaxy clusters, the charged particles making up cosmic rays are moving almost exclusively along (but not across) magnetic field lines. The resulting anisotropic transport…

Astrophysics of Galaxies · Physics 2016-08-31 Ruediger Pakmor , Christoph Pfrommer , Christine M. Simpson , Rahul Kannan , Volker Springel

Cosmic ray (CR)-driven instabilities play a decisive role during particle acceleration at shocks and CR propagation in galaxies and galaxy clusters. These instabilities amplify magnetic fields and modulate CR transport so that the…

High Energy Astrophysical Phenomena · Physics 2021-03-03 Mohamad Shalaby , Timon Thomas , Christoph Pfrommer

We have developed a new, very efficient numerical scheme to solve the CR diffusion convection equation that can be applied to the study of the nonlinear time evolution of CR modified shocks for arbitrary spatial diffusion properties. The…

Astrophysics · Physics 2009-11-11 T. W. Jones , H. Kang

Cosmic rays (CRs) are ubiquitous in the interstellar medium (ISM) of nearby galaxies, but many of their properties are not well-constrained. Gamma-ray observations provide a powerful tool in this respect, allowing us to constrain both the…

High Energy Astrophysical Phenomena · Physics 2023-07-19 Maria Werhahn , Philipp Girichidis , Christoph Pfrommer , Joseph Whittingham

We examine diffusive shock acceleration (DSA) of the pre-exisiting as well as freshly injected populations of nonthermal, cosmic-ray (CR) particles at weak cosmological shocks. Assuming simple models for thermal leakage injection and…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Hyesung Kang , Dongsu Ryu

We analyse the transport of cosmic rays (CR) in magnetic fields that are structured on scales greater than the CR Larmor radius. We solve the Vlasov-Fokker-Planck (VFP) equation for various mixes of mirroring and small-angle scattering and…

High Energy Astrophysical Phenomena · Physics 2025-04-09 A. R. Bell , J. H. Matthews , A. M. Taylor , G. Giacinti

Energetic nonthermal particles (cosmic rays, CRs) are accelerated in supernova remnants, relativistic jets and other astrophysical objects. The CR energy density is typically comparable with that of the thermal components and magnetic…

High Energy Astrophysical Phenomena · Physics 2015-06-15 A. M. Bykov , A. Brandenburg , M. A. Malkov , S. M. Osipov

We present new results characterizing cosmological shocks within adaptive mesh refinement N-Body/hydrodynamic simulations that are used to predict non-thermal components of large-scale structure. This represents the first study of shocks…

We present recent developments of global galactic-scale numerical models of the Cosmic Ray (CR) driven dynamo, which was originally proposed by Parker (1992). We conduct a series of direct CR+MHD numerical simulations of the dynamics of the…

Astrophysics of Galaxies · Physics 2015-05-27 Michał Hanasz , Dominik Wóltański , Kacper Kowalik , Hanna Kotarba

A numerical method for integrating the equations describing a dynamically coupled system made of a fluid and cosmic-rays is developed. In smooth flows the effect of CR pressure is accounted for by modification of the characteristic…

Astrophysics · Physics 2008-11-26 Francesco Miniati

Observations of large-scale radio emissions prove the existence of shock accelerated cosmic-ray electrons in galaxy clusters, while the lack of detected $\gamma$-rays limits the acceleration of cosmic-ray protons in galaxy clusters. This…

High Energy Astrophysical Phenomena · Physics 2020-04-22 Denis Wittor , Franco Vazza , Dongsu Ryu , Hyesung Kang

Low sonic Mach number shocks form in the intracluster medium (ICM) during the formation of the large-scale structure of the universe. Nonthermal cosmic-ray (CR) protons are expected to be accelerated via diffusive shock acceleration (DSA)…

High Energy Astrophysical Phenomena · Physics 2019-10-02 Dongsu Ryu , Hyesung Kang , Ji-Hoon Ha