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Related papers: The cooling function of HD molecule revisited

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We use high signal-to-noise ratio, high-resolution VLT-UVES data of Q J0643-5041 amounting to a total of more than 23 hours exposure time and fit the neutral hydrogen, metals and H2 absorption features with multiple-component Voigt…

Cosmology and Nongalactic Astrophysics · Physics 2014-05-09 D. Albornoz Vásquez , H. Rahmani , P. Noterdaeme , P. Petitjean , R. Srianand , C. Ledoux

The modelling of emission spectra of molecules seen in interstellar clouds requires the knowledge of collisional rate coefficients. Among the commonly observed species, N$_2$H$^+$ is of particular interest since it was shown to be a good…

Astrophysics of Galaxies · Physics 2015-06-23 François Lique , Fabien Daniel , Laurent Pagani , Nicole Feautrier

Atoms and molecules, and in particular CO, are important coolants during the evolution of interstellar star-forming gas clouds. The presence of dust grains, which allow many chemical reactions to occur on their surfaces, strongly impacts…

Solar and Stellar Astrophysics · Physics 2015-06-17 S. Hocuk , S. Cazaux , M. Spaans

We present an experimental study performed on a vibrated granular gas enclosed into a 2D rectangular cell. Experiments are realized in microgravity. High speed video recording and optical tracking allow to obtain the full kinematics…

Soft Condensed Matter · Physics 2014-03-20 Yan Grasselli , Georges Bossis , Romain Morini

The interpretation of water line emission from existing observations and future HIFI/Herschel data requires a detailed knowledge of collisional rate coefficients. Among all relevant collisional mechanisms, the rotational (de)excitation of…

Astrophysics · Physics 2009-11-13 A. Faure , N. Crimier , C. Ceccarelli , P. Valiron , L. Wiesenfeld , M. -L. Dubernet

Kinetic temperature is a fundamental parameter in molecular clouds. Symmetric top molecules, such as NH$_3$ and CH$_3$CCH, are often used as thermometers. However, at high temperatures, NH$_3$(2,2) can be collisionally excited to…

We investigate the bright CO fundamental emission in the central regions of five protostars in their primary mass assembly phase using new observations from JWST's Near-Infrared Spectrograph (NIRSpec) and Mid-Infrared Instrument (MIRI). CO…

Rates for rotational excitation of HC3N by collisions with He atoms and H2 molecules are computed for kinetic temperatures in the range 5-20K and 5-100K, respectively. These rates are obtained from extensive quantum and quasi-classical…

Chemical Physics · Physics 2009-11-13 Michael Wernli , Laurent Wiesenfeld , Alexandre Faure , Pierre Valiron

We introduce a method for classical trajectory calculations to simulate collisions between atoms and large rigid asymmetric-top molecules. Using this method, we investigate the formation of molecule-helium complexes in buffer-gas cooling…

Chemical Physics · Physics 2015-06-03 Zhiying Li , Eric J. Heller

We have chosen a reduced set of 18 ionization rate equations (for ions of H, C, N, O, S and Ne), which allow us to obtain a moderately accurate estimate of the non-equilibrium radiative cooling function. We evaluate the accuracy of this…

Astrophysics · Physics 2009-10-28 A. Raga , G. Mellema , P. Lundqvist

Theoretical and observational arguments suggest that there is a large amount of hot ($\sim 10^6$ K), diffuse gas residing in the Milky Way's halo, while its total mass and spatial distribution are still unclear. In this work, we present a…

Astrophysics of Galaxies · Physics 2020-05-06 Xiang-Er Fang , Fulai Guo , Ye-Fei Yuan

CO plays an important role in interstellar molecular clouds, both as a coolant, and as a diagnostic molecule. However, a proper evaluation of the cooling rate due to CO requires a determination of the populations of many levels, the…

Astrophysics of Galaxies · Physics 2018-11-19 A. P. Whitworth , S. E. Jaffa

We present a formulation for a local cooling function to be employed in the diffuse, hot corona region of 3D GRMHD simulations of accreting black holes. This new cooling function calculates the cooling rate due to inverse Compton scattering…

High Energy Astrophysical Phenomena · Physics 2020-12-02 Brooks E. Kinch , Scott C. Noble , Jeremy D. Schnittman , Julian H. Krolik

The collapse and fragmentation of filamentary primordial gas clouds are explored using 1D and 2D hydrodynamical simulations coupled with the nonequilibrium processes of H2 formation. The simulations show that depending upon the initial…

Astrophysics · Physics 2009-10-31 Fumitaka Nakamura , Masayuki Umemura

ISO has provided us with a new perspective on gas temperatures in photodissociation regions through measurements of line emission from rotationally-excited levels of the H_2 molecule. The H_2 rotational level populations provide a thermal…

Astrophysics · Physics 2007-05-23 B. T. Draine , F. Bertoldi

Cold cores in interstellar molecular clouds represent the very first phase in star formation. The physical conditions of these objects are studied in order to understand how molecular clouds evolve and how stellar masses are determined. The…

Astrophysics · Physics 2009-11-13 J. Harju , M. Juvela , S. Schlemmer , L. K. Haikala , K. Lehtinen , K. Mattila

We use FIRE simulations to study disk formation in z~0, Milky Way-mass galaxies, and conclude that a key ingredient for the formation of thin stellar disks is the ability for accreting gas to develop an aligned angular momentum distribution…

It has been shown that temperatures near the horizon of rotating black holes can be about the phase transition temperature in the Standard Model with the Higgs boson. The distance from the horizon and gravitational and electromagnetic…

General Relativity and Quantum Cosmology · Physics 2022-11-22 A. A. Grib , Yu. V. Pavlov

We use recent observations of the HI-mass function to constrain galaxy formation. The data conflicts with the standard model where most of the gas in a low-mass dark matter halo is assumed to settle into a disk of cold gas that is depleted…

Astrophysics · Physics 2009-11-13 H. J. Mo , Xiaohu Yang , Frank C. van den Bosch , Neal Katz

We study the influence of the choice of cooling function on the formation of molecular clouds in high-resolution three-dimensional simulations of converging flows. We directly compare the results obtained using the simple, parametrized…

Astrophysics of Galaxies · Physics 2015-06-15 Milica Micic , Simon C. O. Glover , Robi Banerjee , Ralf S. Klessen