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Related papers: Cold Clouds as Cosmic-Ray Detectors

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We study the propagation of mildly-relativistic cosmic rays (CRs) in multiphase interstellar medium environments with conditions typical of nearby disk galaxies. We employ the techniques developed in Armillotta+21 to post-process three…

Astrophysics of Galaxies · Physics 2022-05-04 Lucia Armillotta , Eve C. Ostriker , Yan-Fei Jiang

Current predictions for the line ratios from photo-dissociative regions (PDRs) in galaxies adopt theoretical models that consider only individual parcels of PDR gas each characterized by the local density and far-UV radiation field.…

Astrophysics of Galaxies · Physics 2017-03-08 Joseph A. Muñoz , S. Peng Oh

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

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

An ionization plays a key role in formation of stars, planets and their atmospheres. Cosmic rays (CR) are the main source of the ionization, therefore it is important to know and be able to estimate fluxes of galactic and stellar cosmic…

Solar and Stellar Astrophysics · Physics 2019-05-22 A. Struminsky , A. Sadovski

We investigate how cosmic ray (CR) transport in molecular clouds and their substructures can be probed using multi-wavelength observations. The detailed microphysics regulating the penetration and coupling of CRs in dense molecular…

High Energy Astrophysical Phenomena · Physics 2026-05-19 Hayden P. H. Ng , Ellis R. Owen , Naomi Tsuji , Szu-Ting Chen

The Central Molecular Zone (CMZ), located in the centre of the Milky Way, is a roughly cylindrical structure of molecular gas extending up to parsecs around the supermassive black hole Sagittarius A*. The average H2 ionisation rate in the…

High Energy Astrophysical Phenomena · Physics 2025-08-05 Sruthiranjani Ravikularaman , Sarah Recchia , Vo Hong Minh Phan , Stefano Gabici

We investigate the role of cosmic rays from young galaxies in heating and ionizing the intergalactic medium (IGM) at high redshift. Using the IRAS observations at $60 \mu m$, we estimate the cosmic ray luminosity density at the present…

Astrophysics · Physics 2015-06-24 Biman B. Nath , Peter L. Biermann

From the rate of hydrogen ionization and the gamma ray flux, we derived the spectrum of relativistic and subrelativistic cosmic rays (CRs) nearby and inside the molecular cloud Sgr B2 near the Galactic Center (GC). We studied two cases of…

High Energy Astrophysical Phenomena · Physics 2015-08-19 V. A. Dogiel , D. O. Chernyshov , A. M. Kiselev , M. Nobukawa , K. S. Cheng , C. Y. Hui , C. M. Ko , K. K. Nobukawa , T. G. Tsuru

The radiative cooling time of the X-ray-emitting plasma near the center in many clusters of galaxies is shorter than the age of the cluster, but neither the expected large drop in central temperature --nor the expected mass flow towards the…

Astrophysics · Physics 2009-11-07 Sergio Colafrancesco , Arnon Dar , Alvaro De Rujula

We present infrared and millimeter observations of molecular gas, dust and ionized gas towards a sample of clouds distributed along the 500 central pc of the Galaxy. The clouds were selected to investigate the physical state, in particular…

Astrophysics · Physics 2009-11-07 N. J. Rodriguez-Fernandez , J. Martin-Pintado , A. Fuente , T. L. Wilson

Cosmic rays (CRs) are ubiquitous in the interstellar medium (ISM) of nearby galaxies, but many of their properties are not well-constrained. Gamma-ray observations provide a powerful tool in this respect, allowing us to constrain both the…

High Energy Astrophysical Phenomena · Physics 2023-07-19 Maria Werhahn , Philipp Girichidis , Christoph Pfrommer , Joseph Whittingham

The cosmic-ray ionization rate ($\zeta_2$) is one of the key parameters in star formation, since it regulates the chemical and dynamical evolution of molecular clouds by ionizing molecules and determining the coupling between the magnetic…

Astrophysics of Galaxies · Physics 2024-10-23 Gan Luo , Thomas G. Bisbas , Marco Padovani , Brandt A. L. Gaches

The observed bimodality in radio luminosity in galaxy clusters is puzzling. We investigate the possibility that cosmic-ray (CR) streaming in the intra-cluster medium can 'switch off' hadronically induced radio and gamma-ray emission. For…

High Energy Astrophysical Phenomena · Physics 2015-06-15 Joshua Wiener , S Peng Oh , Fulai Guo

The detection of high-energy particles, cosmic rays (CRs), deep inside the heliosphere implies that there are, at least, three distinctly different stages in the lifetime of a CR particle: acceleration, propagation in the interstellar…

Astrophysics · Physics 2007-12-04 Igor V. Moskalenko

The coarse-grained propagation of Galactic cosmic rays (CRs) is traditionally constrained by phenomenological models of Milky Way CR propagation fit to a variety of direct and indirect observables; however, constraining the fine-grained…

Astrophysics of Galaxies · Physics 2024-02-07 Chad Bustard , John Wu

We have analyzed a sample of nearby cool and warm infrared (IR) galaxies using photometric and structural parameters. The set of measures include far-infrared color ($C = \log_{10}[S_{60\mu m}/S_{100\mu m}]$), total IR luminosity…

Astrophysics · Physics 2008-11-26 Nurur Rahman , George Helou , Joseph M. Mazzarella

We derive observational consequences of the hypothesis that cosmic rays (CR's) of energy $>10^{19}eV$ originate in the same cosmological objects producing gamma-ray bursts (GRB's). Inter-galactic magnetic fields $\gtrsim 10^{-12} G$ are…

Astrophysics · Physics 2009-10-28 Jordi Miralda-Escude , Eli Waxman

We present three-dimensional astrochemical simulations and synthetic observations of magnetised, turbulent, self-gravitating molecular clouds. We explore various galactic interstellar medium environments, including cosmic-ray ionization…

Astrophysics of Galaxies · Physics 2021-01-20 Thomas G. Bisbas , Jonathan C. Tan , Kei E. I. Tanaka

The circumgalactic medium (CGM) plays a critical role in galaxy evolution, influencing gas flows, feedback processes, and galactic dynamics. Observations show a substantial cold gas reservoir in the CGM, but the mechanisms driving its…

Astrophysics of Galaxies · Physics 2025-06-11 Matthias Weber , Timon Thomas , Christoph Pfrommer , Ruediger Pakmor