Related papers: OH Evolution in Molecular Clouds

OH masers at 1720 MHz have proven to be excellent indicators of interactions between supernova remnants and molecular clouds. OH excitation calculations suggest that the 6049 MHz OH maser line is excited for higher column densities than for…

As part of the first far-IR line survey towards Orion KL, we present the detection of seven new rotationally excited OH Lambda-doublets (at 48, 65, 71, 79, 98 and 115 um). Observations were performed with the Long Wavelength Spectrometer…

We present observations of 12CO J=1-0, 13CO J=1-0, HI, and all four ground-state transitions of the hydroxyl (OH) radical toward a sharp boundary region of the Taurus molecular cloud. Based on a PDR model that reproduces CO and [CI]…

The Atacama Pathfinder Experiment (APEX) 12m telescope was used to observe the N=1-0, J=0-1 ground state transitions of OH+ at 909.1588 GHz with the CHAMP+ heterodyne array receiver. Two blended hyperfine structure transitions were detected…

We used Arecibo Observatory and the Green Bank Telescope to observe OH in twelve early-type galaxies with known reservoirs of dense gas. We present three new detections of OH in absorption in the 1667 MHz line. One objective of our survey…

We present an analysis of Giant Molecular Clouds (GMCs) within hydrodynamic simulations of isolated, low-mass (M* ~ 10^9 M_sol) disc galaxies. We study the evolution of molecular abundances and the implications for CO emission and the X_CO…

Orion KL has served as a benchmark for spectral line searches throughout the (sub)millimeter regime. The main goal is to systematically study spectral characteristics of Orion KL in the 1.3 cm band. We carried out a spectral line survey…

We model the temperature and chemical structure of molecular clouds as a function of depth into the cloud, assuming a cloud of constant density n illuminated by an external FUV (6 eV < E < 13.6 eV) flux G_0 (scaling factor in multiples of…

The interstellar hydride hydroxyl (OH) is a potential tracer of CO-dark molecular gas. We present new absorption line observations of OH at 18-cm wavelength towards four continuum sources. We compare these to the [CII] line at 1.9 THz…

This paper presents the first substantial study of the chemistry of the envelopes around a sample of 18 low-mass pre- and protostellar objects for which physical properties have previously been derived from radiative transfer modeling of…

We present a new, close relation between column densities of OH and CH molecules based on 16 translucent sightlines (six of them new) and confirm the theoretical oscillator strengths of the OH A--X transitions at 3078 and 3082 \AA (0.00105,…

The most usual tracer of molecular gas is line emission from CO. However, the reliability of that tracer has long been questioned in environments different from the Milky Way. We study the relationship between H2 and CO abundances using a…

Hydroxyl ($\rm OH$) is known to form efficiently in cold gas ($T\sim 100$K) along with the molecule $\rm H_2$ and can be used as an efficient tracer of the diffuse molecular gas in the interstellar medium (ISM). Using a simple formalism…

In order to study a molecular-cloud-scale chemical composition, we have conducted a mapping spectral line survey toward the Galactic molecular cloud W3(OH), which is one of the most active star forming regions in the Perseus arm, with the…

Planck cold clumps are among the most promising objects to investigate the initial conditions of the evolution of molecular clouds. In this work, by combing the dust emission data from the survey of Planck satellite with the molecular data…

We have performed an unbiased dense core survey toward the Orion A Giant Molecular Cloud in the C$^{18}$O ($J$=1--0) emission line taken with the Nobeyama Radio Observatory (NRO) 45-m telescope. The effective angular resolution of the map…

We present the results of a comparative study of HI narrow self-absorption (HINSA), OH, 13CO, and C18O in five dark clouds. The HINSA follows the distribution of the emission of the carbon monoxide isotopologues, and has a characteristic…

We surveyed 81 dense molecular cores associated with regions of massive star formation and Sgr A in the 5_{05}-4_{04} and 10_{010}-9_{09} lines of HNCO. Line emission was detected towards 57 objects. Selected subsamples were also observed…

The HyGAL Stratospheric Observatory for Infrared Astronomy (SOFIA) legacy program aims at characterizing the interstellar medium in the Milky Way using hydrides, [C II], and [O I] absorption lines with the 2.7 m SOFIA telescope toward…

We observed the 9-cm Lambda-doubling lines of CH along the dense filament of TMC-1. The CH column densities were compared with the total H2 column densities derived using the 2MASS NIR data and previously published SCUBA maps and with OH…