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Cosmic rays (CRs) are thought to play a dynamically important role in several key aspects of galaxy evolution, including the structure of the interstellar medium, the formation of galactic winds, and the non-thermal pressure support of…

Astrophysics of Galaxies · Physics 2019-11-19 Yohan Dubois , Benoît Commerçon , Alexandre Marcowith , Loann Brahimi

We study cosmic-ray acceleration in a supernova remnant (SNR) and the escape from it. We model nonthermal particle and photon spectra for the hidden SNR in the open cluster Westerlund 2, and the old-age mixed-morphology SNR W 28. We assume…

High Energy Astrophysical Phenomena · Physics 2014-11-20 Yutaka Fujita , Yutaka Ohira , Shuta J. Tanaka , Fumio Takahara

The acceleration of charged particles at astrophysical collisionless shock waves is one of the best studied processes for the energization of particles to ultrarelativistic energies, required by multifrequency observations in a variety of…

Astrophysics · Physics 2009-11-10 Pasquale Blasi

Recent precise measurements of cosmic ray (CR) spectra show that the energy distribution of protons is softer than those of heavier nuclei, and there are spectral hardenings for all nuclear compositions above $\sim$200 GV. Models proposed…

High Energy Astrophysical Phenomena · Physics 2017-08-02 Yiran Zhang , Siming Liu , Qiang Yuan

We calculate spectra of escaping cosmic rays (CRs) accelerated at shocks produced by expanding Galactic superbubbles powered by multiple supernovae producing a continuous energy outflow in star-forming galaxies. We solve the generalized…

High Energy Astrophysical Phenomena · Physics 2020-01-28 Zhaowei Zhang , Kohta Murase , Peter Mészáros

Radio relics detected in the outskirts of galaxy clusters are thought to trace radio-emitting relativistic electrons accelerated at cosmological shocks. In this study, using the cosmological hydrodynamic simulation data for the large-scale…

High Energy Astrophysical Phenomena · Physics 2015-10-14 Sungwook E. Hong , Hyesung Kang , Dongsu Ryu

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

We simulate time-dependent particle acceleration in the blast wave of a young supernova remnant (SNR), using a Monte Carlo approach for the diffusion and acceleration of the particles, coupled to an MHD code. We calculate the distribution…

High Energy Astrophysical Phenomena · Physics 2015-05-18 K. M. Schure , A. Achterberg , R. Keppens , Jacco Vink

Supernova remnants are believed to be the main sources of galactic Cosmic Rays (CR). Within this framework, particles are accelerated at supernova remnant shocks and then released in the interstellar medium. The mechanism through which CRs…

High Energy Astrophysical Phenomena · Physics 2016-08-19 Lara Nava , Stefano Gabici , Alexandre Marcowith , Giovanni Morlino , Vladimir S. Ptuskin

A shock-accelerated particle flux \propto p^-s, where p is the particle momentum, follows from simple theoretical considerations of cosmic-ray acceleration at nonrelativistic shocks followed by rigidity-dependent escape into the Galactic…

High Energy Astrophysical Phenomena · Physics 2015-06-05 Charles D. Dermer

The formation of collisionless shock fronts is an ubiquitous phenomenon in space plasma environments. In the solar wind shocks might accompany coronal mass ejections, while even more violent events, such as supernovae, produce shock fronts…

High Energy Astrophysical Phenomena · Physics 2020-03-17 Cedric Schreiner , Patrick Kilian , Felix Spanier , Patricio A. Muñoz , Jörg Büchner

The enhanced star forming activity, typical of starburst galaxies, powers strong galactic winds expanding on kiloparsec (kpc) scales and characterized by bubble structures. Here we discuss the possibility that particle acceleration may take…

High Energy Astrophysical Phenomena · Physics 2022-02-15 Enrico Peretti , Giovanni Morlino , Pasquale Blasi , Pierre Cristofari

Without amplification, magnetic fields in expanding ejecta of young supernova remnants (SNRs) will be orders of magnitude below those required to shock accelerate thermal electrons, or ions, to relativistic energies or to produce radio…

Astrophysics · Physics 2009-11-10 Donald C. Ellison , Anne Decourchelle , Jean Ballet

Supernova shocks into dense molecular cores in IC 443 (clumps B, C, and G) and 3C 391 were observed using the Stratospheric Observatory for Infrared Astronomy and complemented by archival data from the Herschel Space Observatory. The pure…

Astrophysics of Galaxies · Physics 2024-11-07 William T. Reach , Ngoc Le Tram , Curtis DeWitt , Pierre Lesaffre , Benjamin Godard , Antoine Gusdorf

Cosmic-ray production in young supernova remnant (SNR) shocks is expected to be efficient and strongly nonlinear. In nonlinear, diffusive shock acceleration, compression ratios will be higher and the shocked temperature lower than…

Astrophysics · Physics 2009-10-31 Donald C. Ellison

Cosmic ray (CR) acceleration at the shock created by the expanding cocoons around active galactic nuclei (AGNs) is studied. It is shown that above the energy $10^{18}$ eV the overall energy spectrum of CRs, produced during the AGN evolution…

Astrophysics · Physics 2009-11-19 E. G. Berezhko

In supernova remnants, the nonlinear amplification of magnetic fields upstream of collisionless shocks is essential for the acceleration of cosmic rays to the energy of the "knee" at 10^{15.5}eV. A nonresonant instability driven by the…

Astrophysics · Physics 2014-11-18 Yutaka Ohira , Brian Reville , John G. Kirk , Fumio Takahara

During the formation of large-scale structures in the universe, weak internal shocks are induced within the hot ICM, while strong accretion shocks arise in the WHIM within filaments, and the warm-cold gas in voids surrounding galaxy…

High Energy Astrophysical Phenomena · Physics 2024-09-30 Hyesung Kang

Merger and accretion shocks in clusters of galaxies can accelerate particles via first order Fermi process. Since this mechanism is believed to be intrinsically efficient, shocks are expected to be modified by the backreaction of the…

Astrophysics · Physics 2009-11-10 Stefano Gabici , Pasquale Blasi

Over the past decades, there has been growing observational and theoretical evidence that cosmic-ray-induced instabilities play an important role in both acceleration and transport of cosmic rays (CRs). For instance, the efficient…

High Energy Astrophysical Phenomena · Physics 2025-10-07 Antonio Capanema , Pasquale Blasi , Emanuele Sobacchi