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We examine the cosmic-ray protons (CRp) accelerated at collisionless shocks in galaxy clusters using cosmological structure formation simulations. We find that in the intracluster medium (ICM) within the virial radius of simulated clusters,…

High Energy Astrophysical Phenomena · Physics 2020-04-08 Ji-Hoon Ha , Dongsu Ryu , Hyesung Kang

Theoretical studies of cosmic ray particle acceleration in the first-order Fermi process at relativistic shocks are reviewed. At the beginning we discuss the acceleration processes acting at mildly relativistic shock waves. An essential…

Astrophysics · Physics 2007-05-23 Michal Ostrowski

We study the generation and distribution of high energy electrons in cosmic environment and their observational consequences by carrying out the first cosmological simulation that includes directly cosmic ray (CR) particles. Starting from…

Astrophysics · Physics 2009-11-07 Francesco Miniati , T. W. Jones , Hyesung Kang , Dongsu Ryu

We have performed magnetohydrodynamical simulations to study the amplification of magnetic fields in the precursors of shock waves. Strong magnetic fields are required in the precursors of the strong shocks that occur in supernova remnants.…

High Energy Astrophysical Phenomena · Physics 2015-06-17 M. Bruggen

It has been suggested that relativistic shocks in extragalactic sources may accelerate the most energetic cosmic rays. However, recent theoretical advances indicating that relativistic shocks are probably unable to accelerate particles to…

High Energy Astrophysical Phenomena · Physics 2016-05-03 Anabella T. Araudo , Anthony R. Bell , Katherine M. Blundell

The early acceleration of protons and electrons in the nonrelativistic collisionless shocks with three obliquities are investigated through 1D particle-in-cell simulations. In the simulations, the charged particles possessing a velocity of…

High Energy Astrophysical Phenomena · Physics 2020-05-06 Jun Fang , Chun-Yan Lu , Jing-Wen Yan , Huan Yu

Context: Diffuse $\gamma$-ray emission from cosmic ray (CR) protons scattering off the gas in the intracluster and intergalactic medium (ICM and IGM) remains out of reach for current observations. Detecting this emission would provide…

High Energy Astrophysical Phenomena · Physics 2025-10-20 Ludwig M. Böss , Ildar Khabibullin , Daniel Karner , Klaus Dolag , Ulrich P. Steinwandel , Elena Hernandez-Martinez , Jenny G. Sorce

Cosmic ray (CR) electrons reveal key insights into the non-thermal physics of the interstellar medium, galaxies, galaxy clusters, and active galactic nuclei by means of their inverse Compton {\gamma}-ray emission and synchrotron emission in…

High Energy Astrophysical Phenomena · Physics 2019-09-24 Georg Winner , Christoph Pfrommer , Philipp Girichidis , Rüdiger Pakmor

Complementary views of galaxy clusters in the radio synchrotron, hard X-ray inverse Compton, and high-energy gamma-ray regimes are critical in calibrating them as high-precision cosmological probes. We present predictions for scaling…

Astrophysics · Physics 2009-11-13 Christoph Pfrommer

Aims: morpholgies, number and energy distributions of Cosmological Shock Waves from a set of ENZO cosmological simulations are produced, along with a study of the connection with Cosmic Rays processes in different environments. Method: we…

Astrophysics · Physics 2008-05-29 F. Vazza , G. Brunetti , C. Gheller

Electron motion in an oblique shock wave is studied by means of a one-dimensional, relativistic, electromagnetic, particle simulation code with full ion and electron dynamics. It is found that an oblique shock can produce electrons with…

Plasma Physics · Physics 2009-10-31 Naoki Bessho , Yukiharu Ohsawa

It is well known that cosmic rays (CRs) contribute significantly to the pressure of the interstellar medium in our own Galaxy, suggesting that they may play an important role in regulating star formation during the formation and evolution…

Astrophysics · Physics 2009-11-11 Martin Jubelgas , Volker Springel , Torsten A. Ensslin , Christoph Pfrommer

It is well known that cosmic rays (CRs) contribute significantly to the pressure of the interstellar medium in our own Galaxy, suggesting that they may play an important role in regulating star formation during the formation and evolution…

Astrophysics · Physics 2007-05-23 Christoph Pfrommer , Volker Springel , Martin Jubelgas , Torsten A. Ensslin

Diffuse, extended radio emission in galaxy clusters, commonly referred to as radio halos, indicate the presence of high energy cosmic ray (CR) electrons and cluster-wide magnetic fields. We can predict from theory the expected surface…

High Energy Astrophysical Phenomena · Physics 2017-11-29 Joshua Wiener , Ellen G. Zweibel , S. Peng Oh

Gas properties in the outer intracluster medium (ICM) are not well-constrained, as traditional probes lose sensitivity at Mpc distances. We show that the morphology of radio relics effectively encodes the power spectrum of the surrounding…

High Energy Astrophysical Phenomena · Physics 2026-04-09 Joseph Whittingham , Christoph Pfrommer , Maria Werhahn , Léna Jlassi , Philipp Girichidis

The underlying physics of giant and mini radio halos in galaxy clusters is still an open question. We find that mini halos (such as in Perseus and Ophiuchus) can be explained by radio-emitting electrons that are generated in hadronic cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2015-12-10 Fabio Zandanel , Christoph Pfrommer , Francisco Prada

X-ray observations of galaxy cluster merger shocks can be used to constrain nonthermal processes in the intracluster medium (ICM). The presence of nonthermal pressure components in the ICM, as well as the shock acceleration of particles and…

Astrophysics · Physics 2011-02-11 Ehud Nakar , Milos Milosavljevic , Daisuke Nagai

The radio mini halos (MH) observed in relaxed clusters probe the presence of relativistic particles on scales of hundreds of kpc, beyond the scales directly influenced by the central AGN, but the nature of the mechanism that produces the…

High Energy Astrophysical Phenomena · Physics 2020-08-12 Alessandro Ignesti , Gianfranco Brunetti , Myriam Gitti , Simona Giacintucci

Clusters of galaxies are storage rooms of cosmic rays. They confine the hadronic component of cosmic rays over cosmological time scales due to diffusion, and the electron component due to energy losses. Hadronic cosmic rays can be…

Astrophysics · Physics 2015-06-24 Pasquale Blasi

With ENZO simulations run on the J\"ulich supercomputers, we have investigated the evolution of magnetic fields in the largest cosmic structures (namely galaxy clusters and filaments connecting them) with unprecedented dynamical range.…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-26 Denis Wittor , Paola Domínguez-Fernández , Franco Vazza , Marcus Brüggen