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Related papers: HD/H$_2$ ratio in the diffuse interstellar medium

200 papers

We gather infrared (IR) photometric data from 8 to 500 microns (Spitzer, WISE, IRAS and Herschel) for all of the HRS galaxies. Draine & Li (2007) models are fit to the data from which the stellar contribution has been carefully removed. We…

We report on new FUSE far-UV spectroscopy of the most metal-poor blue compact dwarf galaxy I Zw 18. The new data represent an improvement over previous FUSE spectra by a factor of 1.7 in the signal-to-noise. Together with a larger spectral…

Astrophysics · Physics 2009-11-07 A. Aloisi , S. Savaglio , T. M. Heckman , C. G. Hoopes , C. Leitherer , K. R. Sembach

H2 is the simplest and the most abundant molecule in the ISM, and its formation precedes the formation of other molecules. Understanding the dynamical influence of the environment and the interplay between the thermal processes related to…

Astrophysics of Galaxies · Physics 2016-02-24 Valeska Valdivia , Patrick Hennebelle , Maryvonne Gérin , Pierre Lesaffre

We extend the analytic theory presented by Sternberg et al. (2014) and Bialy & Sternberg (2016) for the production of atomic hydrogen (HI) via FUV photodissociation at the boundaries of dense interstellar molecular (H$_2$) clouds, to also…

Astrophysics of Galaxies · Physics 2023-10-18 Amiel Sternberg , Shmuel Bialy , Alon Gurman

In diffuse interstellar clouds the chemistry that leads to the formation of the oxygen bearing ions OH+, H2O+, and H3O+ begins with the ionization of atomic hydrogen by cosmic rays, and continues through subsequent hydrogen abstraction…

Current measurements indicate that the deuterium abundance in diffuse interstellar gas varies spatially by a factor of ~4 among sightlines extending beyond the Local Bubble. One plausible explanation for the scatter is the variable…

Astrophysics · Physics 2009-11-10 Jason X. Prochaska , Todd M. Tripp , J. Christopher Howk

Modern observations of the interstellar medium (ISM) in galaxies detect a variety of atomic and molecular species. The goal is to connect these observations to the astrochemical properties of the ISM. 3D hydro-chemical simulations attempt…

Astrophysics of Galaxies · Physics 2019-02-20 Thomas G. Bisbas , Andreas Schruba , Ewine F. van Dishoeck

Analyses of spectra obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite, together with spectra from the Copernicus and IMAPS instruments, reveal an unexplained very wide range in the observed deuterium/hydrogen (D/H)…

C$_2$H is a representative hydrocarbon that is abundant and ubiquitous in the interstellar medium (ISM). To study its chemical properties, we present Submillimeter Array (SMA) observations of the C$_2$H $N=3-2$ and HC$_3$N $J=30-29$…

Solar and Stellar Astrophysics · Physics 2015-08-06 Xue-Jian Jiang , Hauyu Baobab Liu , Qizhou Zhang , Junzhi Wang , Zhi-Yu Zhang , Juan Li , Yu Gao , Qiusheng Gu

We study the CO(1-0)-to-H$_2$ conversion factor ($X_{\rm CO}$) and the line ratio of CO(2-1)-to-CO(1-0) ($R_{21}$) across a wide range of metallicity ($0.1 \leq Z/Z_\odot \leq 3$) in high-resolution (~0.2 pc) hydrodynamical simulations of a…

Astrophysics of Galaxies · Physics 2022-06-01 Chia-Yu Hu , Andreas Schruba , Amiel Sternberg , Ewine F. van Dishoeck

We present a numerical code for continuum radiative transfer that is based on the idea of a `library' describing the relation between the intensity of the local radiation field and the resulting dust emission. With this information and…

Astrophysics · Physics 2009-11-07 M. Juvela , P. Padoan

We extend the non-equilibrium model for the chemical and thermal evolution of diffuse interstellar gas presented in Richings et al. (2014) to account for shielding from the UV radiation field. We attenuate the photochemical rates by dust…

Astrophysics of Galaxies · Physics 2015-06-19 Alexander J. Richings , Joop Schaye , Benjamin D. Oppenheimer

The first observations of deuterium and oxygen in the Local Interstellar Medium (LISM) obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE) can be used to search for local abundance variations. While the very limited sample of…

Astrophysics · Physics 2009-11-07 Gary Steigman

We demonstrate that the observed increase of some nebular line ratios with height above the midplane in the diffuse ionized gas (DIG) in the Milky Way and other galaxies is a natural consequence of the progressive hardening of the radiation…

Astrophysics · Physics 2009-11-10 Kenneth Wood , John S. Mathis

This study aims to determine the main physical parameters (N(H2) hydrogen column density and Td dust temperature) of the Interstellar medium, and their distribution in the extended star-forming region, which includes IRAS 05156+3643,…

Astrophysics of Galaxies · Physics 2021-12-08 E. H. Nikoghosyan , N. M. Azatyan , D. H. Andreasyan , D. S. Baghdasaryan

The submillimeter opacity of dust in the diffuse Galactic interstellar medium (ISM) has been quantified using a pixel-by-pixel correlation of images of continuum emission with a proxy for column density. We used three BLAST bands at 250,…

Understanding the molecular gas content in the interstellar medium (ISM) is crucial for studying star formation and galaxy evolution. The CO-to-H$_2$ ($X_{\rm CO}$) and the [CI]-to-H$_2$ ($X_{\rm CI}$) conversion factors are widely used to…

Context. Recent spectroscopic measurements have revealed absorption from higher rotational levels in C$_2$ than previous observations. These improvements are accompanied by the availability of updated radiative and collisional data. Aims.…

Astrophysics of Galaxies · Physics 2025-05-28 J. Le Bourlot , E. Roueff , S. R. Federman , A. M. Ritchey , D. L. Lambert

Understanding water deuterium fractionation is important for constraining the mechanisms of water formation in interstellar clouds. Observations of HDO and H$_2^{18}$O transitions were carried out towards the high-mass star-forming region…