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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

We explore the impact of cosmic rays (CRs) on cosmological adaptive-mesh refinement simulations of a forming 10^12 Msolar halo, focusing on the circumgalactic medium (CGM), and its resulting low-redshift structure and composition. In…

Astrophysics of Galaxies · Physics 2015-12-23 Munier Salem , Greg L. Bryan , Lauren Corlies

The role of cosmic rays (CR) in the formation and evolution of clusters of galaxies has been much debated. It may well be related to other fundamental questions, such as the mechanism which heats and virializes the intracluster medium…

Astrophysics · Physics 2009-10-30 R. Lieu , W. -H. Ip , W. I. Axford , M. Bonamente

The cosmological 21cm signal is a physics-rich probe of the early Universe, encoding information about both the ionization and the thermal history of the intergalactic medium (IGM). The latter is likely governed by X-rays from…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-17 Fabio Pacucci , Andrei Mesinger , Stefano Mineo , Andrea Ferrara

Supernova energy drives interstellar medium (ISM) turbulence and can help launch galactic winds. What difference does it make if $10\%$ of the energy is initially deposited into cosmic rays? To answer this question and study cosmic-ray…

Astrophysics of Galaxies · Physics 2025-07-15 Roark Habegger , Ellen G. Zweibel

Nonthermal phenomena are ubiquitous in the Universe, and cosmic rays (CRs) play various roles in different environments. When, where, and how CRs are first generated since the Big Bang? We argue that blast waves from the first cosmic…

High Energy Astrophysical Phenomena · Physics 2019-12-16 Yutaka Ohira , Kohta Murase

Latest precise cosmic-ray (CR) measurements and present gamma-ray observations have started challenging our understanding of CR transport and interaction in the Galaxy. Moreover, because the density of CRs is similar to the density of the…

We explore the effects of the expected higher cosmic ray (CR) ionization rates $\zeta_{\rm CR}$ on the abundances of carbon monoxide (CO), atomic carbon (C), and ionized carbon (C$^+$) in the H$_2$ clouds of star-forming galaxies. The study…

Cosmic rays (CRs) are an important component in the interstellar medium (ISM), but their effect on the dynamics of the disk-halo interface (< 10 kpc from the disk) is still unclear. We study the influence of CRs on the gas above the disk…

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

Cosmic rays are charged energetic particles that permeate the interstellar medium. Their sizeable energy share and penetration power makes them essential players in the dynamical and chemical processes that rule Galactic evolution, such as…

High Energy Astrophysical Phenomena · Physics 2026-03-17 Giada Peron , Sarah Recchia , Stefano Menchiari , Alexandre Marcowith , Andrei Bykov , Martin Pohl , Elena Amato

By heating the intergalactic medium (IGM) before reionization, X-rays are expected to play a prominent role in the early Universe. The cosmic 21-cm signal from this "Epoch of Heating" (EoH) could serve as a clean probe of high-energy…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-31 Arpan Das , Andrei Mesinger , Andrea Pallottini , Andrea Ferrara , John H. Wise

During the last decade, cosmological simulations have managed to reproduce realistic and morphologically diverse galaxies, spanning the Hubble sequence. Central to this success was a phenomenological calibration of the few included feedback…

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

Cosmic rays (CRs), from active galactic nuclei (AGN) jets and supernovae (SNe), serve as a significant feedback mechanism influencing emission lines in narrow line region (NLR) clouds. These highly energetic particles, propelled by shocks,…

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

We investigate the 21-cm signature that may arise from the intergalactic medium (IGM) prior to the epoch of full reionization (z>5). In scenarios in which the IGM is reionized by discrete sources of photoionizing radiation, the neutral gas…

Astrophysics · Physics 2009-10-28 Piero Madau , Avery Meiksin , Martin J. Rees

Dynamically, cosmic rays with energies above about one GeV/nucleon may be important agents of galaxy evolution. Their pressures compare with the thermal and magnetic ones impacting galactic gas accretion, fountains and galactic outflows,…

High Energy Astrophysical Phenomena · Physics 2022-05-18 A. Nuñez-Castiñeyra , I. A. Grenier , F. Bournaud , Y. Dubois , F. R. Kamal Youssef , P. Hennebelle

The high-density star formation typical of the merger/starburst events that power the large IR luminosities of Ultra Luminous Infrared Galaxies (ULIRGs) (L_{IR}>10^{12}Lsol) throughout the Universe results to extraordinarily high cosmic ray…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 Padelis P. Papadopoulos

In popular cosmological scenarios, some time beyond a redshift of 10, stars within protogalaxies created the first heavy elements; these systems, together perhaps with an early population of quasars, generated the ultraviolet radiation and…

Astrophysics · Physics 2009-10-31 Piero Madau

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,…