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We discuss new methods to integrate the cosmic ray (CR) evolution equations coupled to magneto-hydrodynamics (MHD) on an unstructured moving mesh, as realised in the massively parallel AREPO code for cosmological simulations. We account for…

Astrophysics of Galaxies · Physics 2017-01-11 C. Pfrommer , R. Pakmor , K. Schaal , C. M. Simpson , V. Springel

The regulation of the baryonic content in dwarf galaxies is a long-standing problem. Supernovae (SNe) are supposed to play a key role in forming large-scale galactic winds by removing important amounts of gas from galaxies. SNe are…

Astrophysics of Galaxies · Physics 2020-07-01 Gohar Dashyan , Yohan Dubois

Supernova remnants (SNRs) have long been suspected to be the primary sources of Galactic cosmic rays. Over the past decades, great strides have been made in the modelling of particle acceleration, magnetic field amplification, and escape…

High Energy Astrophysical Phenomena · Physics 2025-09-25 Anton Stall , Chun Khai Loo , Philipp Mertsch

Stationary solutions to the equations of non-linear diffusive shock acceleration play a fundamental role in the theory of cosmic-ray acceleration. Their existence usually requires that a fraction of the accelerated particles be allowed to…

Astrophysics · Physics 2011-02-11 B. Reville , J. G. Kirk , P. Duffy

We investigate the escape process of cosmic rays (CRs) from perpendicular shock regions of a spherical shock propagating to a circumstellar medium with the Parker-spiral magnetic field. The diffusive shock acceleration in perpendicular…

High Energy Astrophysical Phenomena · Physics 2023-04-06 Shoma F. Kamijima , Yutaka Ohira

In the 1960s, the remnants of supernova explosions (SNRs) were indicated as a possible source of galactic cosmic rays through the Diffusive Shock Acceleration (DSA) mechanism. Since then, the observation of gamma-ray emission from…

High Energy Astrophysical Phenomena · Physics 2024-05-28 Andrea Giuliani , Martina Cardillo

Galactic cosmic rays are believed to be accelerated at supernova remnants via diffusive shock acceleration. Though this mechanism gives fairly robust predictions for the spectrum of particles accelerated at the shock, the spectrum of the…

High Energy Astrophysical Phenomena · Physics 2011-08-25 Stefano Gabici

We examine the test-particle solution for diffusive shock acceleration, based on simple models for thermal leakage injection and Alfv'enic drift. The critical injection rate, \xi_c, above which the cosmic ray (CR) pressure becomes…

High Energy Astrophysical Phenomena · Physics 2015-05-19 Hyesung Kang , Dongsu Ryu

The distribution of the very-high-energy diffuse emission in the inner 200 pc measured by HE.S.S. indicates the existence of a pronounced cosmic-ray (CR) gradient peaking on the Galactic center (GC). Previous studies have shown that these…

High Energy Astrophysical Phenomena · Physics 2021-01-04 L. Jouvin , A. Lemière , R. Terrier

We investigate the dynamical interaction between cosmic rays (CRs) and the multiphase interstellar medium (ISM) using numerical magnetohydrodynamic (MHD) simulations with a two-moment CR solver and TIGRESS simulations of star-forming…

Astrophysics of Galaxies · Physics 2024-01-10 Lucia Armillotta , Eve C. Ostriker , Chang-Goo Kim , Yan-Fei Jiang

Recent cosmic ray (CR) measurements have revealed unexpected anomalies in secondary CRs, namely deviations from the predictions of the so-called standard Galactic CR paradigm regarding the composition and energy spectra of the products of…

High Energy Astrophysical Phenomena · Physics 2024-10-30 Rui-zhi Yang , Felix Aharonian

In this paper, we check in detail the validity of the widely adopted point source approximation for nearby cosmic-ray (CR) sources. Under an energy independent escape model for CRs from the sources, we show that for young nearby sources,…

Astrophysics of Galaxies · Physics 2015-05-30 Satyendra Thoudam , Jörg R. Hörandel

The contribution of the Source Cosmic Rays (SCRs), confined in Supernova Remnants, to the diffuse high energy \gr emission above 1 GeV from the Galactic disk is studied. \grs produced by the SCRs have a much harder spectrum compared with…

Astrophysics · Physics 2010-12-03 Evgeny G. Berezhko , Heinrich J. Voelk

Models for cosmic ray (CR) dynamics fundamentally depend on the rate of CR scattering from magnetic fluctuations. In the ISM, for CRs with energies ~MeV-TeV, these fluctuations are usually attributed either to 'extrinsic turbulence' (ET) -…

High Energy Astrophysical Phenomena · Physics 2022-11-10 Philip F. Hopkins , Jonathan Squire , Iryna S. Butsky , Suoqing Ji

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

The optical and near-IR emission from some classes of supernovae (SNe), including Type IIn and possibly some super-luminous SNe, is likely powered by a collision between the SN ejecta and dense circumstellar material (CSM). We argue that…

High Energy Astrophysical Phenomena · Physics 2014-04-21 Kohta Murase , Todd A. Thompson , Eran O. Ofek

Shocks of supernova remnants (SNRs) accelerate charged particles up to 100 TeV range via diffusive shock acceleration (DSA) mechanism. It is believed that shocks of SNRs are the main contributors to the pool of Galactic cosmic rays,…

High Energy Astrophysical Phenomena · Physics 2023-04-05 Jacco Vink , Aya Bamba

The nonlinear kinetic model of cosmic ray (CR) acceleration in supernova remnants (SNRs) is used to describe the properties of the remnant of SN 1006. It is shown, that the theory fits the existing data in a satisfactory way within a set of…

Astrophysics · Physics 2009-11-07 E. G. Berezhko , L. T. Ksenofontov , H. J. Voelk

According to the most popular model for the origin of cosmic rays (CRs), supernova remnants (SNRs) are the site where CRs are accelerated. Observations across the electromagnetic spectrum support this picture through the detection of…

High Energy Astrophysical Phenomena · Physics 2021-01-27 S. Orlando , M. Miceli , S. Ustamujic , A. Tutone , E. Greco , O. Petruk , F. Bocchino , G. Peres

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