Related papers: CH in absorption in IRAS16293-2422

Water is a sensitive tracer of physical conditions in star-forming regions because of its large abundance variations between hot and cold regions. We use spectrally resolved observations of rotational lines of H$_2$O and its isotopologs…

The Heterodyne Instrument for the Far Infrared (HIFI) aboard the Herschel Space Observatory has acquired high-resolution broadband molecular spectra of star-forming regions in a wavelength range that is mostly inaccessible from ground-based…

In recent years, a plethora of high spectral resolution observations of sub-mm and FIR transitions of methylidene (CH), have demonstrated this radical to be a valuable proxy for H2, that can be used for characterising molecular gas within…

Far-infrared spectroscopy reveals gas cooling and its underlying heating due to physical processes taking place in the surroundings of protostars. These processes are reflected in both the chemistry and excitation of abundant molecular…

We report the detection of the prebiotic molecule CH3NCO in a solar-type protostar, IRAS16293-2422 B. A significant abundance of this species on the surface of the comet 67P/Churyumov-Gerasimenko has been proposed, and it has recently been…

We present newly processed archival Herschel images of molecular cloud MCLD 123.5+24.9 in the Polaris Flare. This cloud contains five starless cores. Using the spectral synthesis code Cloudy, we explore uncertainties in the derivation of…

We present new analytic theory and radiative transfer computations for the atomic to molecular (HI-to-H2) transitions, and the build-up of atomic-hydrogen (HI) gas columns, in optically thick interstellar clouds, irradiated by…

3-Hydroxypropenal (HOCHCHCHO) is the lower energy tautomer of malonaldehyde which displays a complex rotation-tunneling spectrum. It was detected tentatively toward the solar-type protostar IRAS 16293$-$2422 B with ALMA in the framework of…

The CH$^+$ ion is a key species in the initial steps of interstellar carbon chemistry. Its formation in diverse environments where it is observed is not well understood, however, because the main production pathway is so endothermic (4280…

We investigate the column density distribution function of neutral hydrogen at redshift z = 3 using a cosmological simulation of galaxy formation from the OverWhelmingly Large Simulations (OWLS) project. The base simulation includes…

We present the first results on the diffuse transition clouds observed in [CII] line emission at 158 microns (1.9 THz) towards Galactic longitudes near 340deg (5 LOSs) and 20deg (11 LOSs) as part of the GOT C+ survey. Out of the total 146…

A set of new, sensitive, and spectrally resolved, sub-millimeter line observations are used to probe the warm circumstellar gas around the S-type AGB star chi Cyg. The observed lines involve high rotational quantum numbers, which, combined…

Recent submillimeter and far-infrared wavelength observations of absorption in the rotational ground-state lines of various simple molecules against distant Galactic continuum sources have opened the possibility of studying the chemistry of…

Context: Hydrides of the most abundant heavier elements are fundamental molecules in cosmic chemistry. Some of them trace gas irradiated by UV or X-rays. Aims: We explore the abundances of major hydrides in W3 IRS5, a prototypical region of…

We have constructed three-dimensional models for the equilibrium abundance of molecular hydrogen within diffuse interstellar clouds of arbitrary geometry that are illuminated by ultraviolet radiation. The position-dependent photo-…

Photon Dominated Regions (PDRs) are interfaces between the mainly ionized and mainly molecular material around young massive stars. Analysis of the physical and chemical structure of such regions traces the impact of far-ultraviolet…

The chemical composition of the interstellar medium is determined by gas phase chemistry, assisted by grain surface reactions, and by shock chemistry. The aim of this study is to measure the abundance of the hydroxyl radical (OH) in diffuse…

Based on the analysis of available published data and archival data along 24 sightlines (5 of which are new) we derive more accurate estimates of the column densities of OH and CH towards diffuse/translucent clouds and revisit the typically…

We observed the 3335 MHz (9cm) F=1-1 line of CH toward a sample of diffuse clouds occulting compact extragalactic mm-wave continuum sources, using the old NRAO 43m telescope. Because radiofrequency observations of CH really must be…

Molecular hydrogen being unobservable in cold molecular clouds, the column density measurements of molecular gas currently rely either on dust emission observation in the far-IR or on star counting. (Sub-)millimeter observations of numerous…