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The energy spectra of ultra-high energy cosmic rays (CRs) measured with giant extensive air shower (EAS) arrays exhibit discrepancies between the flux intensities and/or estimated CR energies exceeding experimental errors. The well-known…

High Energy Astrophysical Phenomena · Physics 2010-03-22 A. A. Ivanov

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

We use kinetic simulations of diffusive shock acceleration (DSA) to study the time-dependent evolution of plane, quasi-parallel, cosmic-ray (CR) modified shocks. Thermal leakage injection of low energy CRs and finite Alfv\'en wave…

High Energy Astrophysical Phenomena · Physics 2011-02-11 Hyesung Kang , Dongsu Ryu , T. W. Jones

We use a simple model for cosmic ray (CR) production and transport to assess the impact of CRs on $z$\,$=$\,$0$ galaxy, circumgalactic medium (CGM), and halo properties. To do so, we run the first suite of large-volume cosmological…

Astrophysics of Galaxies · Physics 2025-07-02 Rahul Ramesh , Dylan Nelson , Philipp Girichidis

We explore the impact of cosmic rays (CRs) on cosmological adaptive-mesh refinement simulations of a forming 10^12 Msolar halo, focusing on the circumgalactic medium (CGM), and its resulting low-redshift structure and composition. In…

Astrophysics of Galaxies · Physics 2015-12-23 Munier Salem , Greg L. Bryan , Lauren Corlies

We investigate the dynamical importance of a newly recognized possible source of significant feedback generated during structure formation; namely cosmic ray (CR) pressure. We present evidence for the existence of numerous shocks in the hot…

Astrophysics · Physics 2007-05-23 Francesco Miniati , Dongsu Ryu , T. W. Jones , Hyesung Kang

Cosmic rays (CRs) are a plausible mechanism for launching winds of cool material from the discs of star-forming galaxies. However, there is no consensus on what types of galaxies likely host CR-driven winds, or what role these winds might…

Astrophysics of Galaxies · Physics 2021-03-03 Roland M. Crocker , Mark R. Krumholz , Todd A. Thompson

Cosmic rays are transported out of the galaxy by diffusion and advection due to streaming along magnetic field lines and resonant scattering off self-excited MHD waves. Thus momentum is transferred to the plasma via the frozen-in waves as a…

High Energy Astrophysical Phenomena · Physics 2013-04-05 E. A. Dorfi , D. Breitschwerdt

The propagation of charged cosmic rays through the Galactic environment influences all aspects of the observation at Earth. Energy spectrum, composition and arrival directions are changed due to deflections in magnetic fields and…

Instrumentation and Methods for Astrophysics · Physics 2017-07-26 Lukas Merten , Julia Becker Tjus , Horst Fichtner , Björn Eichmann , Günter Sigl

We present and test a general-purpose code, called PPASPH, for evolving self-gravitating fluids in astrophysics, both with and without a collisionless component. In PPASPH, hydrodynamical properties are computed by using the SPH (Smoothed…

Astrophysics · Physics 2009-10-28 Arturo Serna , Jean-Michel Alimi , Jean-Pierre Chieze

The circumgalactic medium (CGM) contains information on the cumulative effect of galactic outflows over time, generally thought to be caused by feedback from star formation and active galactic nuclei. Observations of such outflows via…

Cosmic rays (CRs) are an important component in the interstellar medium (ISM), but their effect on the dynamics of the disk-halo interface (< 10 kpc from the disk) is still unclear. We study the influence of CRs on the gas above the disk…

Cosmic rays (CRs) have recently re-emerged as attractive candidates for mediating feedback in galaxies because of their long cooling timescales. They can have energy densities comparable to the thermal gas, but do not suffer catastrophic…

Astrophysics of Galaxies · Physics 2017-01-25 Joshua Wiener , Christoph Pfrommer , S. Peng Oh

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…

Astrophysics of Galaxies · Physics 2017-04-27 Svenja Jacob , Christoph Pfrommer

Cosmic ray (CR) currents through magnetised plasma drive strong instabilities producing amplification of the magnetic field. This amplification helps explain the CR energy spectrum as well as observations of supernova remnants and radio…

High Energy Astrophysical Phenomena · Physics 2017-07-31 James H. Matthews , Anthony R. Bell , Katherine M. Blundell , Anabella T. Araudo

We study the evolution of an embedded protoplanet in a circumstellar disk using the 3D-Radiation Hydro code TRAMP, and treat the thermodynamics of the gas properly in three dimensions. The primary interest of this work lies in the…

Astrophysics · Physics 2009-11-11 H. Klahr , W. Kley

In order for diffusive shock acceleration (DSA) to accelerate particles to high energies, the energetic particles must be able to interact with magnetic turbulence over a broad wavelength range. The weakly anisotropic distribution of…

High Energy Astrophysical Phenomena · Physics 2015-05-20 A. M. Bykov , S. M. Osipov , D. C. Ellison

We present the results of linear analysis and two-dimensional local magnetohydrodynamic (MHD) simulations of the Parker instability, including the effects of cosmic rays (CRs), in magnetized gas disks (galactic disks). As an unperturbed…

Astrophysics · Physics 2009-11-10 Takuhito Kuwabara , Kenji Nakamura , C. M. Ko

Cosmic ray (CR) feedback is critical for galaxy formation as CRs drive galactic winds, regularize star formation in galaxies, and escape from active galactic nuclei to heat the cooling cores of galaxy clusters. The feedback strength of CRs…

High Energy Astrophysical Phenomena · Physics 2024-06-10 Rouven Lemmerz , Mohamad Shalaby , Christoph Pfrommer , Timon Thomas