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Aims: The gas-phase abundance of methanol in dark quiescent cores in the interstellar medium cannot be explained by gas-phase chemistry. In fact, the only possible synthesis of this species appears to be production on the surfaces of dust…

Astrophysics · Physics 2009-11-13 R. T. Garrod , V. Wakelam , E. Herbst

We present the results of astrochemical modeling of complex organic molecules (COMs) in the ice and gas of the prestellar core L1544 with the recently updated MONACO rate equations-based model. The model includes, in particular,…

Current gas phase models do not account for the abundances of HNCO isomers detected in various environments, suggesting a formation in icy grain mantles. We attempted to study a formation channel of HNCO and its possible isomers by…

Instrumentation and Methods for Astrophysics · Physics 2014-07-07 A. Jiménez-Escobar , B. M. Giuliano , G. M. Muñoz Caro , J. Cernicharo , N. Marcelino

Low energy cosmic rays (up to the GeV energy domain) play a crucial role in the physics and chemistry of the densest phase of the interstellar medium. Unlike interstellar ionising radiation, they can penetrate large column densities of gas,…

High Energy Astrophysical Phenomena · Physics 2022-10-19 S. Gabici

In the earliest phases of star-forming clouds, stable molecular species, such as CO, are important coolants in the gas phase. Depletion of these molecules on dust surfaces affects the thermal balance of molecular clouds and with that their…

Astrophysics of Galaxies · Physics 2016-01-27 S. Hocuk , S. Cazaux , M. Spaans , P. Caselli

One of the most outstanding problems in the gravitational collapse scenario of early structure formation is the cooling of primordial gas to allow for small mass objects to form. As the neutral primordial gas is a poor radiator at…

Astrophysics · Physics 2009-11-13 Jens Jasche , Benedetta Ciardi , Torsten A. Ensslin

Long-chain hydrocarbon anions CnH- (n=4, 6, 8) have recently been found to be abundant in a variety of interstellar clouds. In order to explain their large abundances in the denser (prestellar/protostellar) environments, new chemical models…

Astrophysics of Galaxies · Physics 2015-06-04 M. A. Cordiner , S. B Charnley

Hot corino chemistry and warm carbon chain chemistry (WCCC) are driven by gas-grain interactions in star-forming cores: radical-radical recombination reactions to form complex organic molecules (COMs) in the ice mantle, sublimation of…

Solar and Stellar Astrophysics · Physics 2020-07-15 Yuri Aikawa , Kenji Furuya , Satoshi Yamamoto , Nami Sakai

Surface processes on cosmic solids in cold astrophysical environments lead to gas phase depletion and molecular complexity. Most astrophysical models assume that the molecular ice forms a thick multilayer substrate, not interacting with the…

Astrophysics of Galaxies · Physics 2020-06-17 Alexey Potapov , Cornelia Jäger , Thomas Henning

The first hydrostatic core (FHSC) phase is a brief stage in the protostellar evolution that is difficult to detect. Our goal is to characterize the chemical evolution of gas and dust during the formation of the FHSC. Moreover, we are…

We aim to investigate the chemistry and gas phase abundance of HNCO and the variation of the HNCO/CS abundance ratio as a diagnostic of the physics and chemistry in regions of massive star formation. A numerical-chemical model has been…

Astrophysics of Galaxies · Physics 2015-05-14 D. M. Tideswell , G. A. Fuller , T. J. Millar , A. J. Markwick

Recent observations have revealed significant variations in the abundances of gas- and ice-phase molecules in galaxies with different luminosities and types. In order to discuss the physical origins of these variations, we incorporate gas-…

Astrophysics of Galaxies · Physics 2025-12-16 K. Bekki , K. Furuya , T. Shimonishi

In recent years, exciting developments have taken place in the identification of the role of cosmic rays in star-forming environments. Observations from radio to infrared wavelengths and theoretical modelling have shown that low-energy…

Observations of the emission of the carbon cycle species (C, C+ CO) are commonly used to diagnose gas properties in the interstellar medium but are significantly sensitive to the cosmic-ray ionization rate. The carbon-cycle chemistry is…

Astrophysics of Galaxies · Physics 2022-03-14 Brandt A. L. Gaches , Thomas G. Bisbas , Shmuel Bialy

Context: Complex molecules such as ethanol and dimethyl ether have been observed in a number of hot molecular cores and hot corinos. Attempts to model the molecular formation process using gas phase only models have so far been…

Astrophysics of Galaxies · Physics 2015-05-18 P. Hall , T. J. Millar

Cosmic rays provide an important source for free electrons in the Earth's atmosphere and also in dense interstellar regions where they produce a prevailing background ionization. We utilize a Monte Carlo cosmic ray transport model for…

Solar and Stellar Astrophysics · Physics 2015-06-16 Paul Rimmer , Christiane Helling

We study the change in cosmic-ray pressure, the change in cosmic-ray density, and the level of cosmic-ray induced heating via Alfven-wave damping when cosmic rays move from a hot ionized plasma to a cool cloud embedded in that plasma. The…

Astrophysics of Galaxies · Physics 2015-05-28 John E. Everett , Ellen G. Zweibel

The standard model of cosmic ray heating-induced desorption of interstellar ices is based on a continuous representation of the sporadic desorption of ice mantle components from classical (0.1 micron) dust grains. This has been re-evaluated…

Solar and Stellar Astrophysics · Physics 2022-08-17 Jonathan M. C. Rawlings

The presence of dust can strongly affect the chemical composition of the interstellar medium. We model the chemistry in photodissociation regions (PDRs) using both gas-phase and dust-phase chemical reactions. Our aim is to determine the…

Astrophysics of Galaxies · Physics 2016-06-22 G. B. Esplugues , S. Cazaux , R. Meijerink , M. Spaans , P. Caselli

We investigate the impact of cosmic rays (CRs) on the circumgalactic medium (CGM) in FIRE-2 simulations, for ultra-faint dwarf through Milky Way (MW)-mass halos hosting star-forming (SF) galaxies. Our CR treatment includes injection by…

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