English
Related papers

Related papers: Simple hydrogen-bearing molecules in translucent m…

200 papers

In this Letter we investigate the shape of the probability distribution of column densities (PDF) in molecular clouds. Through the use of low-noise, extinction-calibrated \textit{Herschel}/\textit{Planck} emission data for eight molecular…

Solar and Stellar Astrophysics · Physics 2015-06-23 Marco Lombardi , João Alves , Charles J. Lada

It is well-known that the architecture of macromolecules plays an important role in the hydrodynamics and viscosity of its semi-diluted solutions. However, the systematic study of the rheology of macromolecules with complex topology, such…

Carbon monoxide (CO) is a poor tracer of H$_{2}$ in the diffuse interstellar medium (ISM), where most of the carbon is not incorporated into CO molecules unlike the situation at higher extinctions. We present a novel, indirect method to…

Astrophysics of Galaxies · Physics 2023-12-18 Raphael Skalidis , Paul F. Goldsmith , Philip F. Hopkins , Sam B. Ponnada

The total mass estimate of molecular clouds suffers from the uncertainty in the H$_2$-CO conversion factor, the so-called $X_{\rm CO}$ factor, which is used to convert the $^{12}$CO (1--0) integrated intensity to the H$_2$ column density.…

We report on a comparison between 21 cm rotation measure (RM) and the optically-thin atomic hydrogen column density (N_HI) measured towards unresolved extragalactic sources in the Galactic plane of the northern sky. HI column densities…

Astrophysics of Galaxies · Physics 2015-06-16 Tyler Foster , Roland Kothes , Joanne Brown

Interstellar clouds that exhibit strong Ca I and Fe I lines were called CaFe clouds. The ionisation equilibrium equations were used to model the column densities of Ca II, Ca I, K I, Na I, Fe I and Ti II in CaFe clouds. The chemical…

Astrophysics · Physics 2010-04-28 P. Gnacinski , M. Krogulec

Using data from IRAM's Plateau de Bure Interferometer and 30 m Telescope, we discuss the mm-wave absorption lines of CS, SO, H2S and HCS+ which arise in diffuse clouds occulting several extragalactic continuum sources. Typical relative…

Astrophysics · Physics 2009-11-07 R. Lucas , H. S. Liszt

ABRIDGED: Context: HI and CO large scale surveys of the Milky Way trace the diffuse atomic clouds and the dense shielded regions of molecular hydrogen clouds. However, until recently, we have not had spectrally resolved C+ surveys to…

Astrophysics of Galaxies · Physics 2015-06-18 W. D. Langer , T. Velusamy , J. L. Pineda , K. Willacy , P. F. Goldsmith

We present Far Ultraviolet Spectroscopic Explorer (FUSE) observations of interstellar molecular hydrogen (H_2) in two Galactic high-velocity clouds (HVCs). Molecular hydrogen absorption is detected in the Magellanic Stream (abundance ~0.3…

Astrophysics · Physics 2009-11-07 Philipp Richter , Kenneth R. Sembach , Bart P. Wakker , Blair D. Savage

Aims: We derive the probability density functions (PDFs) of column density for a complete sample of prominent molecular cloud complexes closer than 200 pc. Methods: We derive near-infrared dust extinction maps for 23 molecular cloud…

Astrophysics of Galaxies · Physics 2015-05-14 J. Kainulainen , H. Beuther , T. Henning , R. Plume

We have obtained OH spectra of four transitions in the $^2\Pi_{3/2}$ ground state, at 1612, 1665, 1667, and 1720 MHz, toward 51 sightlines that were observed in the Herschel project Galactic Observations of Terahertz C+. The observations…

As a complement to the HyGAL Stratospheric Observatory for Infrared Astronomy Legacy Program, we report the results of a ground-based absorption line survey of simple molecules in diffuse and translucent Galactic clouds. Using the Institut…

The rotational transitions of carbon monoxide (CO) are the primary means of investigating the density and velocity structure of the molecular interstellar medium. Here we study the lowest four rotational transitions of CO towards…

Astrophysics · Physics 2009-10-31 James G. Ingalls , T. M. Bania , Adair P. Lane , Matthias Rumitz , Antony A. Stark

How complex organic - and potentially prebiotic - molecules are formed in regions of low- and high-mass star-formation remains a central question in astrochemistry. In particular, with just a few sources studied in detail, it is unclear…

Astrophysics of Galaxies · Physics 2015-10-14 Julie M. Lykke , Cécile Favre , Edwin A. Bergin , Jes K. Jørgensen

Massive young stellar objects (MYSOs) with hot cores are classic sources of complex organic molecules. The origins of these molecules in such sources, as well as the small- and large-scale differentiation between nitrogen- and…

Solar and Stellar Astrophysics · Physics 2015-03-25 Edith C. Fayolle , Karin I. Öberg , Robin T. Garrod , Ewine F. van Dishoeck , Suzanne E. Bisschop

The observed molecular properties of a sample of FIR-luminous and OH megamaser (OH-MM) galaxies have been investigated. The ratio of high and low-density tracer lines is found to be determined by the progression of the star formation in the…

Astrophysics · Physics 2009-11-13 A. F. Loenen , W. A. Baan , M. Spaans

We have observed the HC3N (J=10-9) and N2H+ (J=1-0) lines toward the Vela C molecular clouds with the Mopra 22 m telescope to study chemical characteristics of dense cores. The intensity distributions of these molecules are similar to each…

The Chamaeleon molecular cloud complex is one of the nearest star-forming sites encompassing three molecular clouds with a different star-formation history, from quiescent (Cha III) to actively forming stars (Cha II), and reaching the end…

The mobility of lighter species on the surface of interstellar dust grains plays a crucial role in forming simple through complex molecules. Carbon monoxide is one of the most abundant molecules, its surface diffusion on the grain surface…

Astrophysics of Galaxies · Physics 2022-03-30 Kinsuk Acharyya

We report two detections of deuterated molecular hydrogen (HD) in QSO absorption-line systems at $z > 2$. Toward J2123-0500, we find $N$(HD) $= 13.84 \pm 0.2$ for a sub-DLA with metallicity $\simeq 0.5Z_{\odot}$ and $N$(H$_2$) = $17.64 \pm…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-19 J. Tumlinson , A. L. Malec , R. F. Carswell , M. T. Murphy , R. Buning , N. Milutinovic , S. L. Ellison , J. X. Prochaska , R. A. Jorgenson , W. Ubachs , A. M. Wolfe