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We construct a model for cosmic ray acceleration from protostellar accretion shocks and calculate the resulting cosmic ray ionization rate within star-forming molecular clouds. We couple a protostar cluster model with an analytic accretion…

Astrophysics of Galaxies · Physics 2018-07-25 Brandt A. L. Gaches , Stella S. R. Offner

Galactic cosmic rays (CR) are particles presumably accelerated in supernova remnant shocks that propagate in the interstellar medium up to the densest parts of molecular clouds, losing energy and their ionisation efficiency because of the…

High Energy Astrophysical Phenomena · Physics 2016-05-25 M. Padovani , A. Marcowith , P. Hennebelle , K. Ferrière

We investigate the ionization of the diffuse interstellar medium by cosmic rays by modeling their propagation along the wandering magnetic fields using a Monte Carlo method. We study how low-energy cosmic rays propagate in turbulent,…

High Energy Astrophysical Phenomena · Physics 2022-12-05 Riccardo Franceschi , Steven Neil Shore

Galactic cosmic rays are a ubiquitous source of ionisation of the interstellar gas, competing with UV and X-ray photons as well as natural radioactivity in determining the fractional abundance of electrons, ions and charged dust grains in…

High Energy Astrophysical Phenomena · Physics 2018-06-27 Marco Padovani , Alexei V. Ivlev , Daniele Galli , Paola Caselli

Cosmic rays (CRs) are the primary driver of ionization in star forming molecular clouds (MCs). Despite their potential impacts on gas dynamics and chemistry, no simulations of star cluster formation following the creation of individual…

Astrophysics of Galaxies · Physics 2024-07-26 Margot Fitz Axen , Stella Offner , Phillip F. Hopkins , Mark R. Krumholz , Michael Y. Grudic

Cosmic rays (CR) play an important role in dense molecular cores, affecting their thermal and dynamical evolution and initiating the chemistry. Several studies have shown that the formation of protostellar discs in collapsing clouds is…

Astrophysics of Galaxies · Physics 2015-06-17 Marco Padovani , Patrick Hennebelle , Daniele Galli

We study the capability of low-energy cosmic rays (CR) to penetrate into diffuse clouds when they move from the hot ionized plasma to a cool cloud embedded in that plasma. The spectrum of CR inside a cloud can be remarkably different from…

High Energy Astrophysical Phenomena · Physics 2014-10-30 Giovanni Morlino , Stefano Gabici

Low-energy cosmic rays are a fundamental source of ionization for molecular clouds, influencing their chemical, thermal and dynamical evolution. The purpose of this work is to explore the possibility that a low-energy component of…

Solar and Stellar Astrophysics · Physics 2015-05-13 Marco Padovani , Daniele Galli , Alfred E. Glassgold

We investigate ionization and heating of gas in the dense, shielded clumps/cores of molecular clouds bathed by an influx of energetic, charged cosmic rays (CRs). These molecular clouds have complex structures, with substantial variation in…

Astrophysics of Galaxies · Physics 2021-06-02 Ellis R. Owen , Alvina Y. L. On , Shih-Ping Lai , Kinwah Wu

Understanding the cosmic ray (CR) ionization rate is crucial in order to simulate the dynamics of, and interpret the chemical species observed in molecular clouds. Calculating the CR ionization rate requires both accurate knowledge of the…

High Energy Astrophysical Phenomena · Physics 2019-07-10 Kedron Silsbee , Alexei V. Ivlev

Cosmic rays are an important source of heating in the interstellar medium, in particular in dense molecular cloud cores shielded from the external ultraviolet radiation field. The limits placed on the cosmic-ray ionization rate from…

Solar and Stellar Astrophysics · Physics 2015-02-12 Daniele Galli , Marco Padovani

Starburst galaxies are efficient $\gamma$-ray producers, because their high supernova rates generate copious cosmic ray (CR) protons, and their high gas densities act as thick targets off which these protons can produce neutral pions and…

High Energy Astrophysical Phenomena · Physics 2020-02-26 Mark R. Krumholz , Roland M. Crocker , Siyao Xu , A. Lazarian , M. T. Rosevear , Jasper Bedwell-Wilson

Low-energy cosmic rays, in particular protons with energies below 1 GeV, are significant drivers of the thermochemistry of molecular clouds. However, these cosmic rays are also greatly impacted by energy losses and magnetic field transport…

High Energy Astrophysical Phenomena · Physics 2021-09-08 Brandt A. L. Gaches , Stefanie Walch , Alex Lazarian

Diffuse interstellar clouds show large abundances of H_3^+ which can be maintained only by a high ionization rate of H_2. Cosmic rays are the dominant ionization mechanism in this environment, so the large ionization rate implies a high…

High Energy Astrophysical Phenomena · Physics 2011-02-11 Nick Indriolo , Brian D. Fields , Benjamin J. McCall

The main signature of the interaction between cosmic rays and molecular clouds is the high ionisation degree. This decreases towards the densest parts of a cloud, where star formation is expected, because of energy losses and magnetic…

Solar and Stellar Astrophysics · Physics 2015-10-21 Marco Padovani , Patrick Hennebelle , Alexandre Marcowith , Katia Ferrière

Molecular clouds are complex magnetized structures, with variations over a broad range of length scales. Ionization in dense, shielded clumps and cores of molecular clouds is thought to be caused by charged cosmic rays (CRs). These CRs can…

Astrophysics of Galaxies · Physics 2021-07-27 Ellis R. Owen , Alvina Y. L. On , Shih-Ping Lai , Kinwah Wu

Cosmic rays (CR) propagate through the galactic scales down to the smaller scales at which stars form. CRs are close to energy equipartition with the other components of the interstellar medium and can provide a support against gravity if…

Astrophysics of Galaxies · Physics 2019-02-13 Benoît Commerçon , Alexandre Marcowith , Yohan Dubois

Cosmic rays (CRs) can significantly impact dense molecular clouds in galaxies, heating the interstellar medium (ISM) and altering its chemistry, ionization, and thermal properties. Their influence is particularly relevant in environments…

Astrophysics of Galaxies · Physics 2026-05-20 E. Koutsoumpou , J. A. Fernández-Ontiveros , K. M. Dasyra , L. Spinoglio

Cosmic rays (CRs) are a dynamically important component of the interstellar medium (ISM) of galaxies. The $\sim$GeV CRs that carry most CR energy and pressure are likely confined by self-generated turbulence, leading them to stream along…

Astrophysics of Galaxies · Physics 2022-11-16 Matt L. Sampson , James R. Beattie , Mark R. Krumholz , Roland M. Crocker , Christoph Federrath , Amit Seta

Cosmic-rays constitute the main ionising and heating agent in dense, starless, molecular cloud cores. We reexamine the physical quantities necessary to determine the cosmic-ray ionisation rate (especially the cosmic ray spectrum at E < 1…

Astrophysics of Galaxies · Physics 2015-06-16 Marco Padovani , Daniele Galli
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