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Related papers: The Implications of a High Cosmic-Ray Ionization R…

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Molecular clouds are expected to emit non-thermal radiation due to cosmic ray interactions in the dense magnetized gas. Such emission is amplified if a cloud is located close to an accelerator of cosmic rays and if energetic particles can…

High Energy Astrophysical Phenomena · Physics 2015-05-13 Stefano Gabici , Felix A. Aharonian , Sabrina Casanova

Cosmic rays are predominantly accelerated in shocks associated with star formation such as supernova remnants and stellar wind bubbles, so the cosmic-ray flux and thus cosmic-ray ionization rate, $\zeta_{\rm H}$, should correlate with the…

Astrophysics of Galaxies · Physics 2018-10-02 Nick Indriolo , E. A. Bergin , E. Falgarone , B. Godard , M. A. Zwaan , D. A. Neufeld , M. G. Wolfire

We study the streaming instability of GeV$-100~$GeV cosmic rays (CRs) and its damping in the turbulent interstellar medium (ISM). We find that the damping of streaming instability is dominated by ion-neutral collisional damping in weakly…

High Energy Astrophysical Phenomena · Physics 2022-03-14 Siyao Xu , Alex Lazarian

We present a detailed calculation of the propagation of AGN-like ionizing radiation through the intergalactic space. We model the ionization state of absorbing clouds, and show that the universe will be more opaque above $4\,$Ryd than…

Astrophysics · Physics 2009-10-28 Francesco Haardt , Piero Madau

We study the combined impact of magnetic mirroring and focusing on the ionization by cosmic rays (CRs) in dense molecular clouds and circumstellar disks. We show that for effective column densities of up to $\sim10^{25}$ cm$^{-2}$ (where…

High Energy Astrophysical Phenomena · Physics 2018-08-29 Kedron Silsbee , Alexei V. Ivlev , Marco Padovani , Paola Caselli

The propagation of Galactic Cosmic Ray nuclei having energies between 100 MeV/nuc and several PeV/nuc is strongly believed to be of diffusive nature. The particles emitted by a source located in the disk do not pervade the whole Galaxy, but…

Astrophysics · Physics 2009-11-07 Richard Taillet , David Maurin

Cosmic rays (CRs) at sub-TeV energies play a fundamental role in the chemical and dynamical evolution of molecular clouds, as they control the ionisation, dissociation, and excitation of H$_{2}$. Their characterisation is important both for…

A theory of cosmic-ray transport in multi-phase diffusive media is developed, with the specific application to cases in which the cosmic-ray diffusion coefficient has large spatial fluctuations that may be inherently multi-scale. We…

How cosmic rays sample the multi-phase interstellar medium (ISM) in starburst galaxies has important implications for many science goals, including evaluating the cosmic ray calorimeter model for these systems, predicting their neutrino…

High Energy Astrophysical Phenomena · Physics 2013-11-22 Erin Boettcher , Ellen G. Zweibel , Tova M. Yoast-Hull , J. S. Gallagher

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 theoretically study dissociative ionization of H$_2^+$ exposed to strong linearly polarized few-cycle visible, near-infrared and midinfrared laser pulses. We find rich energy-sharing structures in the combined electron and nuclear…

Atomic Physics · Physics 2016-03-15 Lun Yue , Lars Bojer Madsen

We develop a theory to account for the cosmic ray spectrum between 1 GeV and 10^4 GeV following the earlier papers of this series. We use the basic concept that the cosmic ray particles are accelerated in a supernova shock that travels…

Astrophysics · Physics 2007-05-23 Peter L. Biermann , Richard G. Strom

Molecular clouds are expected to emit non-thermal radiation due to cosmic ray interactions in the dense magnetized gas. Such emission is amplified if a cloud is located close to an accelerator of cosmic rays and if cosmic rays can leave the…

Astrophysics · Physics 2009-11-13 Stefano Gabici , Sabrina Casanova , Felix A. Aharonian

During the solar journey through galactic space, variations in the physical properties of the surrounding interstellar medium (ISM) modify the heliosphere and modulate the flux of galactic cosmic rays (GCR) at the surface of the Earth, with…

Astrophysics of Galaxies · Physics 2015-05-20 Priscilla C. Frisch , Hans-Reinhard Mueller

Galactic cosmic rays (CRs) play a crucial role in ionisation, dissociation, and excitation processes within dense cloud regions where UV radiation is absorbed by dust grains and gas species. CRs regulate the abundance of ions and radicals,…

We present results of a deep spectroscopic survey designed to quantify the statistics of the escape of ionizing photons from star-forming galaxies at z~3. We measure the ratio of ionizing to non-ionizing UV flux density <f900/f1500>_obs,…

Astrophysics of Galaxies · Physics 2018-12-26 C. C. Steidel , M. Bogosavljevic , A. E. Shapley , N. A. Reddy , G. C. Rudie , M. Pettini , R. F. Trainor , A. L. Strom

We investigate the propagation of ultra-high energy cosmic ray nuclei (A = 1-56) from cosmologically distant sources through the cosmic radiation backgrounds. Various models for the injected composition and spectrum and of the cosmic…

Astrophysics · Physics 2014-10-13 Dan Hooper , Subir Sarkar , Andrew M. Taylor

In a previous work we investigated the propagation of fast moving charged particles in a spatially constant but slowly time dependent pseudoscalar background, such as the one provided by cold relic axions. The background induces cosmic rays…

High Energy Physics - Phenomenology · Physics 2015-03-17 D. Espriu , F. Mescia , A. Renau

HD molecule is one the most abundant molecule in the Universe and due to its sensibility to the conditions in the medium, it can be used to constrain physical parameters in the medium where HD resides. Lately we have shown that HD abundance…

Astrophysics of Galaxies · Physics 2023-09-06 D. N. Kosenko , S. A. Balashev

The spatial clustering of galaxies in galaxy clusters implies that the background of infrared (IR) light in the intracluster medium (ICM) may exceed the universal background. Cosmic rays injected within the ICM propagate diffusively and at…

Astrophysics · Physics 2009-11-13 Daniel De Marco , Pasquale Blasi , Patricia Hansen , Todor Stanev