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Related papers: A Simple Sub-Grid Model For Cosmic Ray Effects on …

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Cosmological hydrodynamical simulations of galaxy evolution are increasingly able to produce realistic galaxies, but the largest hurdle remaining is in constructing subgrid models that accurately describe the behavior of stellar feedback.…

Astrophysics of Galaxies · Physics 2015-06-12 Cameron Hummels , Greg Bryan , Britton Smith , Matthew Turk

Cosmic ray (CR) electrons are key tracers of non-thermal processes in galaxies, yet their spectra are often modelled under the untested assumption of steady state between injection and cooling. In this work, we present a time-dependent…

Observations of diffuse Galactic gamma-ray spectrum by the EGRET instrument reveal an excess above ~ 1 GeV over the expected gamma-ray spectrum calculated under the assumption that the locally observed cosmic-ray (CR) spectra represent the…

Astrophysics · Physics 2009-11-11 Thoudam Satyendra

We performed high-resolution simulations of a sample of 14 galaxy clusters that span a mass range from 5 x 10^13 M_solar/h to 2 x 10^15 M_solar/h to study the effects of cosmic rays (CRs) on thermal cluster observables such as X-ray…

Galaxy evolution is shaped by star formation and stellar feedback at scales unresolved by current high-resolution cosmological simulations. Precise subgrid models are thus necessary, and different approaches have been developed. However,…

Astrophysics of Galaxies · Physics 2026-02-17 Maxime Rey , Jérémy Blaizot , Taysun Kimm , Joakim Rosdahl , Léo Michel-Dansac

Using an idealized set-up, we investigate the dynamical role of cosmic rays (CRs) in the early stages of galactic outflows for galaxies of halo masses $10^{8}$, $10^{11}$ and $10^{12}$ $M_\odot$. The outflow is launched from a central…

Astrophysics of Galaxies · Physics 2020-08-04 Ranita Jana , Siddhartha Gupta , Biman B. Nath

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 origin of cosmic rays is one of the long-standing mysteries in physics and astrophysics. Simple arguments suggest that a scenario of supernova remnants (SNRs) in the Milky Way as the dominant sources for the cosmic ray population below…

High Energy Astrophysical Phenomena · Physics 2016-06-01 Julia Becker Tjus , Björn Eichmann , Mike Kroll , Nils Nierstenhöfer

The Milky Way's galactic center is a highly dynamical, crowded environment. Gamma ray observations of this region, such as the excess of GeV scale gamma rays observed by Fermi LAT, have been of tremendous interest to both the high energy…

High Energy Astrophysical Phenomena · Physics 2025-09-24 Isabel S. Sands , Philip F. Hopkins , Sam B. Ponnada , Dusan Keres , Lina Necib , Yen-Hsing Julius Lin

Galaxy evolution is driven by star formation and stellar feedback on scales unresolved by current high-resolution cosmological simulations, requiring robust subgrid models. However, these models remain degenerate, often calibrated primarily…

Astrophysics of Galaxies · Physics 2026-02-17 Maxime Rey , Jérémy Blaizot , Taysun Kimm , Joakim Rosdahl , Léo Michel-Dansac , Valentin Mauerhofer

The advent of new sub-millimeter observational facilities has stimulated the desire to model the sub-mm line emission of galaxies within cosmological galaxy formation models. This is typically done in post-processing by applying…

Astrophysics of Galaxies · Physics 2018-11-14 Gergö Popping , Desika Narayanan , Rachel S. Somerville , Andreas L. Faisst , Mark R. Krumholz

Numerical simulations have become a necessary tool to describe the complex interactions among the different processes involved in galaxy formation and evolution, unfeasible via an analytic approach. The last decade has seen a great effort…

Astrophysics of Galaxies · Physics 2017-07-19 Alessandro Lupi , Marta Volonteri , Joseph Silk

The circumgalactic medium (CGM) of star-forming dwarf galaxies plays a key role in regulating the galactic baryonic cycle. We investigate how susceptible the CGM of dwarf satellite galaxies is to ram pressure stripping (RPS) in Milky…

Astrophysics of Galaxies · Physics 2024-10-10 Jingyao Zhu , Stephanie Tonnesen , Greg L. Bryan , Mary E. Putman

Observations of the $\gamma$-ray emission around star clusters, isolated supernova remnants, and pulsar wind nebulae indicate that the cosmic-ray (CR) diffusion coefficient near acceleration sites can be suppressed by a large factor…

Astrophysics of Galaxies · Physics 2021-04-07 Vadim A. Semenov , Andrey V. Kravtsov , Damiano Caprioli

Magnetic fields are widely observed in the Universe in virtually all astrophysical objects, from individual stars to entire galaxies, even in the intergalactic medium, but their specific generation has long been debated. Due to the…

Astrophysics of Galaxies · Physics 2017-11-08 Michael Rieder , Romain Teyssier

We introduce a novel diffusion model for the propagation of cosmic rays (CRs) that incorporates an anisotropic diffusion tensor of a general form within a realistically modeled large-scale Galactic magnetic field. The parameters of the…

High Energy Astrophysical Phenomena · Physics 2025-07-22 V. D. Borisov , V. O. Yurovsky , I. A. Kudryashov

We review some recent findings on diffusion of cosmic rays (CRs) in magnetohydrodynamic (MHD) turbulence obtained by adopting the numerically-tested model of MHD turbulence, including perpendicular superdiffusion of CRs, inefficient…

High Energy Astrophysical Phenomena · Physics 2021-10-19 Siyao Xu

We study the production of cosmic rays (CRs) in supernova remnants (SNRs), including the reacceleration of background galactic cosmic rays (GCRs) - thus refining the early considerations by Blandford & Ostriker (1980) and Wandel et al.…

Astrophysics · Physics 2007-05-23 E. G. Berezhko , L. T. Ksenofontov , V. S. Ptuskin , V. N. Zirakashvili , H. J. Voelk

More and more observations have indicated the existence of slow diffusion phenomena in astrophysical environments, such as around the supernova remnants and pulsar $\gamma$-ray halos, where the diffusion coefficient of cosmic rays (CRs)…

High Energy Astrophysical Phenomena · Physics 2025-06-24 Yawen Xiao , Jianfu Zhang , Siyao Xu

The majority of galactic baryons reside outside of the galactic disk in the diffuse gas known as the circumgalactic medium (CGM). While state-of-the art simulations excel at reproducing galactic disk properties, many struggle to drive…

Astrophysics of Galaxies · Physics 2018-12-05 Iryna Butsky , Thomas R. Quinn
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