Results 21 to 30 of about 3,801,891 (296)

Origin of CH⁺ in diffuse molecular clouds [PDF]

Astronomy & Astrophysics, 2017
Context. Molecular clouds are known to be magnetised and to display a turbulent and complex structure where warm and cold phases are interwoven. The turbulent motions within molecular clouds transport molecules, and the presence of magnetic fields induces a relative velocity between neutrals and ions known as the ion-neutral drift (vd).
Valdivia, Valeska, Godard, Benjamin, Hennebelle, Patrick, Gerin, Maryvonne, Lesaffre, Pierre, Le Bourlot, Jacques   +5 more
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The CH⁺abundance in turbulent, diffuse molecular clouds [PDF]

Monthly Notices of the Royal Astronomical Society, 2015
The intermittent dissipation of interstellar turbulence is an important energy source in the diffuse ISM. Though on average smaller than the heating rates due to cosmic rays and the photoelectric effect on dust grains, the turbulent cascade can channel large amounts of energy into a relatively small fraction of the gas that consequently undergoes ...
Myers, Andrew, McKee, Christopher, Li, Pak Shing   +2 more
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The Transition from Diffuse Molecular Gas to Molecular Cloud Material in Taurus [PDF]

The Astrophysical Journal, 2021
Abstract We study four lines of sight that probe the transition from diffuse molecular gas to molecular cloud material in Taurus. Measurements of atomic and molecular absorption are used to infer the distribution of species and the physical conditions toward stars behind the Taurus Molecular Cloud (TMC).
S. R. Federman, Johnathan S. Rice, A. M. Ritchey, Hwihyun Kim, John H. Lacy, Paul F. Goldsmith, Nicolas Flagey, Gregory N. Mace, David L. Lambert   +8 more
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Diffuse molecular clouds at high galactic latitude [PDF]

Symposium - International Astronomical Union, 1991
The IRAS 60 and 100 μ m flux from cirrus clouds are commonly explained by dust continuum emission. But this explanation in some cases requires unexpectedly high dust temperatures. We argue that the contribution of fine structure ...
openaire   +1 more source

The Behavior of Selected Diffuse Interstellar Bands with Molecular Fraction in Diffuse Atomic and Molecular Clouds [PDF]

The Astrophysical Journal, 2017
Abstract We study the behavior of eight diffuse interstellar bands (DIBs) in different interstellar environments, as characterized by the fraction of hydrogen in molecular form (f H2), with comparisons to the corresponding behavior of various known atomic and molecular species. The equivalent widths of the five “normal”
Haoyu Fan, Daniel E. Welty, Donald G. York, Paule Sonnentrucker, Julie A. Dahlstrom, Noah Baskes, Scott D. Friedman, Lewis M. Hobbs, Zihao Jiang, Brian Rachford, Theodore P. Snow, Reid Sherman, Gang Zhao   +12 more
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Understanding star formation in molecular clouds IV. Column density PDFs from quiescent to massive molecular clouds [PDF]

, 2022
Astronomy and Astrophysics in presssWe present N-PDFs of 29 Galactic regions obtained from Herschel imaging at high angular resolution, covering diffuse and quiescent clouds, and those showing low-, intermediate-, and high-mass star formation (SF), and ...
Federrath, C., Klessen, R. S., Ward-Thompson, D., P. Didelon, R. Simon, Könyves, V., PEZZUTO, Stefania, Soler, J., Pezzuto, S., R. S. Klessen, A. Kritsuk, Di Francesco, J., F. Motte, Elia, D., N. Schneider, D. Elia, Bontemps, S., Koenyves, V., J. Di Francesco, Clarke, S., A. Roy, C. Federrath, S. Clarke, Kabanovic, S., Ph. André, André, Ph, D. Ward-Thompson, Beattie, J. R., Dib, S., Kritsuk, A., Robitaille, J. F., S. Dib, D. Arzoumanian, Arzoumanian, D., Myers, Ph., D. Seifried, T. Veltchev, Veltchev, T., B. Ladjelate, ELIA, Davide Quintino, Ossenkopf-Okada, V., Seifried, D., V. Könyves, Roy, A., Ph. Myers, S. Kabanovic, J. F. Robitaille, Motte, F., Bonne, L., Andre, Ph., Didelon, P., J. R. Beattie, T. Csengeri, S. Pezzuto, Myers, Ph, S. Bontemps, Schneider, N., Csengeri, T., L. Bonne, Ladjelate, B., J. Soler, Simon, R., V. Ossenkopf-Okada   +62 more
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Molecular Formation in Hot Diffuse Clouds [PDF]

Symposium - International Astronomical Union, 1980
A description is given of the processes of molecular formation and destruction in diffuse interstellar clouds and detailed models of the clouds lying towards ζ Ophiuchi, ζ Persei and o Persei are used to assess the validity of gas phase chemistry. Modifications that may arise from shock-heated regions are discussed.
openaire   +1 more source

CH observations of diffuse molecular clouds

The Astrophysical Journal, 1989
A survey of CH 3.3 GHz emission from a sample of high-latitude molecular clouds, diffuse clouds, and heavily reddened globular clusters is presented. The F = 1-1 main-line transition was detected in every molecular cloud in the sample and in two out of four globular cluster lines of sight. The high rate of detections in the low-extinction high-latitude
Loris Magnani, Elizabeth A. Lada, Goran Sandell, Leo Blitz   +3 more
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Estimating molecular hydrogen in diffuse interstellar clouds [PDF]

Monthly Notices of the Royal Astronomical Society, 1989
La densite de colonne de l'hydrogene moleculaire dans les nuages interstellaires diffus peut etre estimee de maniere satisfaisante par 2 methodes: a partir de la densite de colonne de l'hydrogene atomique combinee avec E(B-V); et a partir des observations optiques des molecules ...
W. B. Somerville, C. A. Smith
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Denoising Diffusion Probabilistic Models to Predict the Density of Molecular Clouds

The Astrophysical Journal, 2023
Abstract We introduce the state-of-the-art deep-learning denoising diffusion probabilistic model as a method to infer the volume or number density of giant molecular clouds (GMCs) from projected mass surface density maps. We adopt magnetohydrodynamic simulations with different global magnetic field strengths and large-scale dynamics, i.e.
Duo Xu, Jonathan C. Tan, Chia-Jung Hsu, Ye Zhu   +3 more
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