相关论文: Cloud Structure and Physical Conditions in Star-Fo…

We present high-resolution optical spectra (at ~0.6--1.8 km s-1) of interstellar CN, CH, CH^+, \ion{Ca}{1}, \ion{K}{1}, and \ion{Ca}{2} absorption toward 29 lines of sight in three star-forming regions, \rho Oph, Cep OB2, and Cep OB3. The…

(Abridged) We carried out a comprehensive far-ultraviolet (UV) survey of ^12CO and H_2 column densities along diffuse molecular Galactic sight lines in order to explore in detail the relationship between CO and H_2. We measured new CO…

The formation of stars is inextricably linked to the structure of their parental molecular clouds. Here we take a number of nearby giant molecular clouds (GMCs) and analyse their column density and mass distributions. This investigation is…

We investigate the chemical evolution of a forming molecular cloud behind an interstellar shock wave. We conduct three-dimensional magnetohydrodynamics simulations of the converging flow of atomic gas, including a simple chemical network…

Molecular clouds are regions of dense gas and dust in space where new stars and planets are born. There is a strong correlation between the distribution of dust and molecular gas in molecular clouds. The present work focuses on the…

The chemical composition of diffuse interstellar clouds is not fully established. They host an active chemistry despite their relatively low density and the ubiquitous presence of far-UV radiation. To further explore the chemical…

We present high-resolution observations of interstellar CN, CH, CH^{+}, \ion{Ca}{1}, and \ion{Ca}{2} absorption lines toward the multiple star systems HD206267 and HD217035. Substantial variations in CN absorption are observed among three…

Near ultraviolet observations of OH+ and OH in diffuse molecular clouds reveal a preference for different environments. The dominant absorption feature in OH+ arises from a main component seen in CH+ (that with the highest CH+/CH column…

We investigate the correlation between OH and H2 column densities in diffuse Galactic clouds, in order to identify potential molecular tracers of interstellar H2. For this, we analyse near-UV spectra extracted from the ESO/VLT archives…

The diffuse and translucent molecular clouds traced in absorption along the line of sight to strong background sources have so far been investigated mainly in the spectral domain because of limited angular resolution or small sizes of the…

We used archival data acquired with the Copernicus satellite to reexamine CO column densities because self-consistent oscillator strengths are now available. Our focus is on lines of sight containing modest amounts of molecular species. Our…

Using archival, high-resolution far-ultraviolet HST/STIS spectra of 34 Galactic O and B stars, we measure CI column densities and compare them with measurements from the literature of CO and H_2 with regard to understanding the presence of…

Star formation activity in molecular clouds is often found to be correlated with the amount of material above a column density threshold of $\sim 10^{22} \, {\rm cm^{-2}}$. Attempts to connect this column density threshold to a ${\it…

We present a comprehensive examination of interstellar P and Cl abundances based on an analysis of archival spectra acquired with the Space Telescope Imaging Spectrograph of the Hubble Space Telescope and the Far Ultraviolet Spectroscopic…

We introduce a model for the large-scale, global 3D structure of molecular clouds. Motivated by the morphological appearance of clouds in surface density maps, we model clouds as cylinders, with the aim of backing out information about the…

Stars form within molecular clouds, so characterizing the physical states of molecular clouds is key in understanding the process of star formation. Cloud structure and stability is frequently assessed using metrics including the virial…

The 1-50 GHz GBT PRIMOS data contains ~50 molecular absorption lines observed in diffuse and translucent clouds located in the Galactic Center, Bar, and spiral arms in the line-of-sight to Sgr B2(N). We measure the column densities and…

$Aims.$ We characterize the molecular-line emission of three clouds whose star-formation rates span one order of magnitude: California, Perseus, and Orion A. $Methods.$ We use stratified random sampling to select positions representing the…

Emission from carbon monoxide (CO) is ubiquitously used as a tracer of dense star forming molecular clouds. There is, however, growing evidence that a significant fraction of CO emission originates from diffuse molecular gas. Quantifying…

We report the first ensemble results from the FUSE survey of molecular hydrogen in lines of sight with A_V $\gtrsim$ 1 mag. We have developed techniques for fitting computed profiles to the low-J lines of H2, and thus determining column…