Results 121 to 130 of about 49,075 (253)

Interstellar shocks and molecular CH/+/ in diffuse clouds

The Astrophysical Journal, 1980
The influence of shocks on the abundances of molecules in diffuse interstellar clouds is investigated with special emphasis on molecular CH/sup +/. Idealized shocks with plausible parameters are found to produce column densities for CH/sup +/ in the hot, postshock gas which are comparable with measured values in interstellar clouds (up to about 10/sup ...
M. Elitzur, W. D. Watson
openaire   +1 more source

The Chemistry of Interstellar OH+, H2O+, and H3O+: Inferring the Cosmic Ray Ionization Rates from Observations of Molecular Ions

, 2012
We model the production of OH+, H2O+, and H3O+ in interstellar clouds, using a steady state photodissociation region code that treats the freeze-out of gas species, grain surface chemistry, and desorption of ices from grains.
Badnell, Bakes, Cartledge, D. Neufeld, Dalgarno, David Hollenbach, Draine, Goicoechea, Goicoechea, Habing, Heiles, Heiles, Hollenbach, Indriolo, Indriolo, J. R. Goicoechea, Jensen, Jensen, Jochims, Joulain, Krełowski, Le Petit, M. J. Kaufman, M. Wolfire, Mathis, Meyer, Rimmer, Sofia, Weingartner, Weingartner, Wolfire, Wolfire   +31 more
core   +1 more source

On the chemistry of hydrides of N atoms and O$^+$ ions [PDF]

, 2016
Previous work by various authors has suggested that the detection by Herschel/HIFI of nitrogen hydrides along the low density lines of sight towards G10.6-0.4 (W31C) cannot be accounted for by gas-phase chemical models.
Awad, Zainab, Viti, Serena, Williams, David A.   +2 more
core   +2 more sources

Composition, structure and chemistry of interstellar dust [PDF]

The observational constraints on the composition of the interstellar dust are analyzed. The dust in the diffuse interstellar medium consists of a mixture of stardust (amorphous silicates, amorphous carbon, polycyclic aromatic hydrocarbons, and graphite ...
Allamandola, Louis J., Tielens, Alexander G. G. M.   +1 more
core   +1 more source

The first results from the Herschel-HIFI mission

, 2012
This paper contains a summary of the results from the first years of observations with the HIFI instrument onboard ESA's Herschel space observatory. The paper starts by outlining the goals and possibilities of far-infrared and submillimeter astronomy ...
van der Tak, Floris
core   +2 more sources

A search for interstellar H2O(+) in diffuse clouds

The Astrophysical Journal, 1984
Searches for H2O(+) toward HD 187982, Zeta Oph, O micron Per, and Zeta Per have yielded significant upper limits for H2O(+) when compared with existing models for similar lines of sight. Using available oscillator strength data, the column density for HD 187982, for example, cannot exceed 3 x 10 to the 12th per sq cm H2O(+) molecules.
Wm. H. Smith, W. V. Schempp, S. R. Federman   +2 more
openaire   +1 more source

The Spectral Energy Distribution of Self-gravitating Interstellar Clouds I. Spheres

, 2007
We derive the spectral energy distribution (SED) of dusty, isothermal, self gravitating, stable and spherical clouds externally heated by the ambient interstellar radiation field.
Bernard J. P., Bernard J. P., Bonnor W. B., Boulanger F., Chlewicki G., Ebert R., Gail H.-P., Jörg Fischera, Laureijs R. J., Lehtinen K., Lehtinen K., Lehtinen K., Lemke D., Mathis J. S., Mattila K., Michael A. Dopita, Ossenkopf V., Padoan P.   +17 more
core   +1 more source

Mapping the Cosmic-Ray Ionization Rate in the Local Galaxy with

The Astrophysical Journal
Chemistry in diffuse molecular clouds relies primarily on rapid ion-molecule reactions. Formation of the initial ions, H ^+ and H ${}_{2}^{+}$ , is dominated by cosmic-ray ionization of H and H _2 , making the cosmic-ray ionization rate (denoted ζ (X ...
Nick Indriolo, Alexei V. Ivlev, T. Pellegrin, M. Obolentseva, Paola Caselli, A. M. Jacob, D. A. Neufeld, Kedron Silsbee, M. G. Wolfire   +8 more
doaj   +1 more source

Galactic Cosmic Ray Interaction with the Perseus Giant Molecular Cloud Using Geant4 Monte Carlo Simulation

Universe
Galactic cosmic rays (GCRs), composed of protons and atomic nuclei, are accelerated in sources such as supernova remnants and pulsar wind nebulae, reaching energies up to the PeV range.
Luan Torres, Luiz Augusto Stuani Pereira
doaj   +1 more source

Molecular Hydrogen Formation via Vibrational Excitation of Partially Superhydrogenated Pyrenes

The Astrophysical Journal
While polycyclic aromatic hydrocarbons (PAHs) are now accepted to be abundant in interstellar space, the abundance and influence of superhydrogenated PAHs (HPAHs) in the interstellar medium (ISM) are still under investigation.
Frederik Doktor S. Simonsen, Rijutha Jaganathan, Julianna Palotás, Zeyuan Tang, Bjørk Hammer, Jos Oomens, Liv Hornekær   +6 more
doaj   +1 more source