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Related papers: Cosmic-ray heating of molecular cloud cores

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The problem of the origin of cosmic rays in the shocks produced by supernova explosions at energies below the so called 'knee' (at ~3*10$^6$ GeV) in the energy spectrum is addressed, with special attention to the propagation of the…

Astrophysics · Physics 2008-11-26 A. D. Erlykin , A. A. Lagutin , A. W. Wolfendale

The 500 central pc of the Galaxy (hereafter GC) exhibit a widespread gas component with a kinetic temperature of 100-200 K. The bulk of this gas is not associated to the well-known thermal radio continuum or far infrared sources like Sgr A…

Astrophysics · Physics 2009-11-10 N. J Rodriguez-Fernandez , J. Martin-Pintado , A. Fuente , T. L. Wilson

$\textit{Herschel}$ observations of far infrared N$^+$ emission lines have demonstrated that dense plasma, with $n_e\sim30\,{\rm cm^{-3}}$, is ubiquitous in the inner Galactic plane. By combining the information from $\textit{Herschel}$…

Astrophysics of Galaxies · Physics 2022-05-03 Marisa Geyer , Mark Walker

Large reservoirs of cold (~ 10^4 K) gas exist out to and beyond the virial radius in the circumgalactic medium (CGM) of all types of galaxies. Photoionization modeling suggests that cold CGM gas has significantly lower densities than…

We model the photoelectric emission from and charging of interstellar dust and obtain photoelectric gas heating efficiencies as a function of grain size and the relevant ambient conditions. Using realistic grain size distributions, we…

Astrophysics · Physics 2011-06-21 Joseph C. Weingartner , B. T. Draine

We present results from radiation non-ideal magnetohydrodynamics (MHD) calculations that follow the collapse of rotating, magnetised, molecular cloud cores to stellar densities. These are the first such calculations to include all three…

Solar and Stellar Astrophysics · Physics 2018-02-07 James Wurster , Matthew R. Bate , Daniel J. Price

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

We elaborate on the dynamics of ionized interstellar medium in the presence of hidden photon dark matter. Our main focus is the ultra-light regime, where the hidden photon mass is smaller than the plasma frequency in the Milky Way. We point…

High Energy Physics - Phenomenology · Physics 2018-10-19 Sergei Dubovsky , Guzmán Hernández-Chifflet

The study of the gamma-ray radiation produced by cosmic rays that escape their accelerators is of paramount importance for (at least) two reasons: first, the detection of those gamma-ray photons can serve to identify the sources of cosmic…

High Energy Astrophysical Phenomena · Physics 2015-06-15 Stefano Gabici

(abridged) The dominant thermal mechanisms in the neutral interstellar medium, which acts as a star-forming gas reservoir, are uncertain in extremely metal-poor galaxies. Our objective is to identify the heating mechanisms in one such…

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

Ionized nebulae have been targets of interest since the introduction of the telescope centuries ago. These isolated, "classical" H II regions gave us some of the earliest insight into the copious feedback energy that stars inject into the…

Astrophysics of Galaxies · Physics 2016-06-09 L. M. Haffner

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

Our Galaxy is the largest nuclear interaction experiment which we know, because of the interaction between cosmic ray particles and the interstellar material. Cosmic rays are particles, which have been accelerated in the Galaxy or in…

Astrophysics · Physics 2011-04-15 Peter L. Biermann

(Abridged) Cosmic rays (CRs) are thought to provide an important source of ionization in the outermost and densest regions of protoplanetary disks; however, it is unknown to what degree they are physically present. As is observed in the…

Solar and Stellar Astrophysics · Physics 2015-06-16 L. Ilsedore Cleeves , Fred C. Adams , Edwin A. Bergin

Context: The study of dust emission at millimeter wavelengths is important to shed light on the dust properties and physical structure of pre-stellar cores, the initial conditions in the process of star and planet formation. Aims: Using two…

In a previous paper we identified cores within infrared dark clouds (IRDCs). We regarded those without embedded sources as the least evolved, and labelled them starless. Here we identify the most isolated starless cores and model them using…

It was recently discovered that in some regions of the Galaxy, the cosmic ray (CR) abundance is several orders of magnitude higher than previously thought. Additionally, there is evidence that in molecular cloud envelopes, the CR ionization…

High Energy Astrophysical Phenomena · Physics 2020-10-21 Kedron Silsbee , Alexei V. Ivlev

We have calculated the radiation field, dust grain temperatures, and far infrared emissivity of numerical models of turbulent molecular clouds. When compared to a uniform cloud of the same mean optical depth, most of the volume inside the…

Astrophysics · Physics 2009-11-10 Thomas Bethell , Ellen Zweibel , Fabian Heitsch , J. S. Mathis

We present an observational and theoretical study of the ionization fraction in several massive cores located in regions that are currently forming stellar clusters. Maps of the emission from the J = 1-> O transitions of C18O, DCO+, N2H+,…

Astrophysics · Physics 2009-10-30 Edwin A. Bergin , Rene Plume , Jonathan P. Williams , Philip C. Myers