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Related papers: Cosmic ray driven dynamo in galactic disks. A para…

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Recent gamma-ray observations reveal inhomogeneous diffusion of cosmic rays (CRs) in the interstellar medium (ISM). This is expected as the diffusion of CRs depends on the properties of turbulence, which can vary widely in the multi-phase…

High Energy Astrophysical Phenomena · Physics 2021-12-15 Siyao Xu

The ordered magnetic field observed via polarized synchrotron emission in nearby disc galaxies can be explained by a mean-field dynamo operating in the diffuse interstellar medium (ISM). Additionally, vertical-flux initial conditions are…

Astrophysics of Galaxies · Physics 2016-01-06 A. Bendre , O. Gressel , D. Elstner

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

Arguably the main challenge of galactic magnetism studies is to explain how the interstellar medium of galaxies reaches energetic equipartition despite the extremely weak cosmic primordial magnetic fields that are originally predicted to…

Astrophysics of Galaxies · Physics 2018-06-20 Sergio Martin-Alvarez , Julien Devriendt , Adrianne Slyz , Romain Teyssier

We investigate the dynamical impact of cosmic rays in cosmological simulations of galaxy formation using adaptive-mesh refinement simulations of a $10^{12}$ solar mass halo. In agreement with previous work, a run with only our standard…

Astrophysics of Galaxies · Physics 2015-06-23 Munier Salem , Greg L. Bryan , Cameron Hummels

Observations show that the magnetic field in young supernova remnants (SNRs) is significantly stronger than can be expected from the compression of the circumstellar medium (CSM) by a factor of four expected for strong blast waves.…

Astrophysics of Galaxies · Physics 2009-08-05 K. M. Schure , J. Vink , A. Achterberg , R. Keppens

Low-mass galaxies radio observations show in many cases surprisingly high levels of magnetic field. The mass and kinematics of such objects do not favour the development of effective large-scale dynamo action. We attempted to check if the…

Astrophysics of Galaxies · Physics 2018-03-14 Hubert Siejkowski , Marian Soida , Krzysztof T. Chyzy

We present non-radiative, cosmological zoom-simulations of galaxy cluster formation with magnetic fields and (anisotropic) thermal conduction of one very massive galaxy cluster with a mass at redshift zero that corresponds to…

Cosmology and Nongalactic Astrophysics · Physics 2022-07-20 Ulrich P. Steinwandel , Ludwig M. Boess , Klaus Dolag , Harald Lesch

State of the art models of the ISM use adaptive mesh refinement to capture small scale structures, by refining on the fly those regions of the grid where density and pressure gradients occur, keeping at the same time the existing resolution…

Astrophysics · Physics 2007-05-23 M. A. de Avillez , Dieter Breitschwerdt

The energy densities in magnetic fields and cosmic rays (CRs) in galaxies are often assumed to be in equipartition, allowing for an indirect estimate of the magnetic field strength from the observed radio synchrotron spectrum. However, both…

Astrophysics of Galaxies · Physics 2016-01-27 Tova M. Yoast-Hull , John S. Gallagher , Ellen G. Zweibel

The ISM of active galaxy centers is exposed to a combination of cosmic ray, FUV and X-ray radiation. We apply PDR models to this ISM with both `normal' and highly elevated (5\times 10^{-15}s^-1) cosmic-ray rates and compare the results to…

Astrophysics · Physics 2011-02-11 R. Meijerink , M. Spaans , F. P. Israel

Galactic cosmic rays (CRs) play a crucial role in galaxy formation and evolution by altering gas dynamics and chemistry across multiple scales. Typical numerical simulations of CR transport assume a constant diffusion coefficient for the…

Astrophysics of Galaxies · Physics 2025-10-16 Sarah Thiele , Romain Teyssier

Galaxies at high redshifts with strong star formation are sources of high-energy cosmic rays. These cosmic rays interact with the baryon and radiation fields of the galactic environment via photo-pair, photo-pion and proton-proton processes…

High Energy Astrophysical Phenomena · Physics 2017-08-24 Ellis R. Owen , Kinwah Wu , Pooja Surajbali , Idunn B. Jacobsen

Magnetic fields are an important component of the interstellar medium (ISM) of galaxies. The thermal gas in the ISM has a multiphase structure, broadly divided into ionised, atomic, and molecular phases. The connection between the…

Astrophysics of Galaxies · Physics 2025-04-01 Amit Seta , N. M. McClure-Griffiths

We study the combined impact of magnetic mirroring and focusing on the ionization by cosmic rays (CRs) in dense molecular clouds and circumstellar disks. We show that for effective column densities of up to $\sim10^{25}$ cm$^{-2}$ (where…

High Energy Astrophysical Phenomena · Physics 2018-08-29 Kedron Silsbee , Alexei V. Ivlev , Marco Padovani , Paola Caselli

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 present a scenario for efficient magnetization of very young galaxies about 0.5 Gigayears after the Big-Bang by a cosmic ray-driven dynamo. These objects experience a phase of strong star formation during this first $10^9$ years. We…

Astrophysics · Physics 2009-11-07 H. Lesch , M. Hanasz

When a magnetised, thermal plasma containing a shock wave efficiently accelerates Cosmic Rays (CR) a reaction is exerted on the fluid structure. The simplest description of this process involves three conservation equations for the…

Astrophysics · Physics 2007-05-23 P. Duffy , L. O'C. Drury , H. J. Voelk

The physics of Cosmic ray (CR) transport remains a key uncertainty in assessing whether CRs can produce galaxy-scale outflows consistent with observations. In this paper, we elucidate the physics of CR-driven galactic winds for CR transport…

Astrophysics of Galaxies · Physics 2021-11-24 Eliot Quataert , Todd A. Thompson , Yan-Fei Jiang

Current-day cosmic ray (CR) propagation studies use static Milky-Way models and fit parametrized source distributions to data. Instead, we use three-dimensional magneto-hydrodynamical (MHD) simulations of isolated galaxies with the…

High Energy Astrophysical Phenomena · Physics 2021-05-25 Maria Werhahn , Christoph Pfrommer , Philipp Girichidis , Ewald Puchwein , Rüdiger Pakmor
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