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Related papers: A Revised Description of the Cosmic Ray-Induced De…

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We examine in detail the recent proposal that extreme Cosmic-Ray-Dominated-Regions (CRDRs) characterize the ISM of galaxies during events of high-density star formation, fundamentally altering its initial conditions (Papadopoulos 2010).…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Padeli P. Papadopoulos , Wing-Fai Thi , Francesco Miniati , Serena Viti

We investigate the impact of cosmic rays (CRs) on the circumgalactic medium (CGM) in FIRE-2 simulations, for ultra-faint dwarf through Milky Way (MW)-mass halos hosting star-forming (SF) galaxies. Our CR treatment includes injection by…

The physical conditions in a collapsing cloud can be traced by observations of molecular lines. To correctly interpret these observations the abundance distributions of the observed species need to be derived. The chemistry in a collapsing…

Solar and Stellar Astrophysics · Physics 2009-11-13 R. J. van Weeren , C. Brinch , M. R. Hogerheijde

Galactic cosmic rays (CRs) are a fundamental non-thermal component of the interstellar medium (ISM). Understanding the transport of super-high-energy particles is essential for interpreting observations of Galactic PeVatrons. Classical…

High Energy Astrophysical Phenomena · Physics 2026-04-07 Yue Hu

Understanding the history and evolution of small bodies, such as dust grains and comets, in planet-forming disks is very important to reveal the architectural laws responsible for the creation of planetary systems. These small bodies in…

Astrophysics of Galaxies · Physics 2018-10-10 Alexey Potapov , Cornelia Jäger , Thomas Henning

We investigate how cosmic rays (CRs) affect thermal and hydrostatic stability of circumgalactic (CGM) gas, in simulations with both CR streaming and diffusion. Local thermal instability can be suppressed by CR-driven entropy mode…

Astrophysics of Galaxies · Physics 2023-05-25 Tsun Hin Navin Tsung , S. Peng Oh , Chad Bustard

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

Cosmic rays (CRs) heavily impact the chemistry and physics of cold and dense star-forming regions. However, characterising their ionisation rate is still challenging from an observational point of view. In the past, a few analytical…

Astrophysics of Galaxies · Physics 2024-02-19 E. Redaelli , S. Bovino , A. Lupi , T. Grassi , D. Gaete-Espinoza , G. Sabatini , P. Caselli

Stars and planets form within cold, dark molecular clouds. In these dense regions, where starlight cannot penetrate, cosmic rays (CRs) are the dominant source of ionization -- driving interstellar chemistry(Dalgarno (2006, PNAS, 103,…

Interstellar dust grain growth in dense clouds and protoplanetary disks, even moderate, affects the observed interstellar ice profiles as soon as a significant fraction of dust grains is in the size range close to the wave vector at the…

Astrophysics of Galaxies · Physics 2022-10-26 Emmanuel Dartois , Jennifer A. Noble , Nathalie Ysard , Karine Demyk , Marin Chabot

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

Context: Chemical models of dense cloud cores often utilize the so-called pseudo-time-dependent approximation, in which the physical conditions are held fixed and uniform as the chemistry occurs. In this approximation, the initial…

Solar and Stellar Astrophysics · Physics 2015-05-18 G. E. Hassel , E. Herbst , E. A. Bergin

The temperatures of dust grains play important roles in the chemical evolution of molecular clouds. Unlike large grains, the temperature fluctuations of small grains induced by photons may be significant. Therefore, if the grain size…

Earth and Planetary Astrophysics · Physics 2018-06-27 Long-Fei Chen , Qiang Chang , Hong-Wei Xi

Gaseous H2O has been detected in several cold astrophysical environments, where the observed abundances cannot be explained by thermal desorption of H2O ice or by H2O gas phase formation. These observations hence suggest an efficient…

Astrophysics · Physics 2011-02-11 Karin I. Oberg , Harold Linnartz , Ruud Visser , Ewine F. van Dishoeck

Low-energy cosmic rays (CRs) are confined by self-generated MHD waves in the mostly neutral ISM. We show that the CR transport equation can be expressed as a continuity equation for the CR number density involving an effective convection…

Astrophysics · Physics 2009-11-10 Paolo Padoan , John Scalo

Methanol is formed via surface reactions on icy dust grains. Methanol is also detected in the gas-phase at temperatures below its thermal desorption temperature and at levels higher than can be explained by pure gas-phase chemistry. The…

Solar and Stellar Astrophysics · Physics 2018-05-02 N. F. W. Ligterink , C. Walsh , R. G. Bhuin , S. Vissapragada , J. Terwisscha van Scheltinga , H. Linnartz

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 2007-05-23 Christoph Pfrommer , Volker Springel , Martin Jubelgas , Torsten A. Ensslin

The chemistry of shielded molecular gas is primarily driven by energetic, charged particles dubbed cosmic rays (CRs), in particular those with energies under 1 GeV. CRs ionize molecular hydrogen and helium, the latter of which contributes…

Astrophysics of Galaxies · Physics 2026-04-01 Arghyadeb Roy , Brandt A. L. Gaches , Jonathan C. Tan

In the absence of magnetic fields and cosmic rays, radiative cooling laws with a range of dependences on temperature affect the stability of interstellar gas. For about four and a half decades, astrophysicists have recognised the importance…

Astrophysics of Galaxies · Physics 2011-08-08 T. W. Hartquist , A. Y. Wagner , S. A. E. G. Falle , J. M. Pittard , S. Van Loo

The astronomical gas-phase detection of simple species and small organic molecules in cold pre-stellar cores, with abundances as high as $\sim$$10^{-8}-10^{-9}$ n$_\text{H}$, contradicts the generally accepted idea that at $10$ K, such…

Astrophysics of Galaxies · Physics 2018-06-19 K-J Chuang , G Fedoseev , D Qasim , S Ioppolo , EF van Dishoeck , H Linnartz