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We present the results of N2H+(1-0) observations of 35 dense molecular cloud cores from the northern and southern hemispheres where massive stars and star clusters are formed. Line emission has been detected in 33 sources, for 28 sources…

Astrophysics · Physics 2009-11-07 L. Pirogov , I. Zinchenko , P. Caselli , L. E. B. Johansson , P. C. Myers

We report the discovery of propylene (also called propene, CH_2CHCH_3) with the IRAM 30-m radio telescope toward the dark cloud TMC-1. Propylene is the most saturated hydrocarbon ever detected in space through radio astronomical techniques.…

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

We present an analysis of gas densities in the central R=300 parsecs of the Milky Way, focusing on three clouds: GCM-0.02-0.07 (the 50 km/s cloud), GCM-0.13-0.08 (the 20 km/s cloud), and GCM0.25+0.01 (the "Brick"). Densities are determined…

Astrophysics of Galaxies · Physics 2018-11-28 E. A. C. Mills , A. Ginsburg , K. Immer , J. M Barnes , L. Wiesenfeld , A. Faure , M. R. Morris , M. A. Requena-Torres

We attempt to characterise the chemical properties of a sample of massive clumps of IRDCs through multi-molecular line observations. We also search for possible evolutionary trends among the derived chemical parameters. The clumps are…

Astrophysics of Galaxies · Physics 2015-06-17 Oskari Miettinen

The study of multiple molecular spectral lines in gas infalling sources can provide the physical and chemical properties of these sources and help us estimate their evolutionary stages. We report line detections within the 3 mm band using…

Astrophysics of Galaxies · Physics 2025-04-09 Yang Yang , Xi Chen , ZhiBo Jiang , Zhiwei Chen , Shuling Yu , Jun Li

Aims. We aim to systematically study the properties of the different transitions of the dense molecular gas tracer HC3N in galaxies. Methods. We have conducted single-dish observations of HC3N emission lines towards a sample of nearby…

Astrophysics of Galaxies · Physics 2017-03-22 Xue-Jian Jiang , Jun-Zhi Wang , Yu Gao , Qiu-Sheng Gu

We have conducted a mapping spectral line survey toward the Galactic giant molecular cloud W51 in the 3 mm band with the Mopra 22 m telescope in order to study an averaged chemical composition of the gas extended over a molecular cloud…

We present search results of 22 high latitude (b > 25 deg.) sightlines for OH 18-cm emission using the 305-m radio telescope at the Arecibo Observatory. These sightlines appear in neutral hydrogen emission at intermediate velocities (V_lsr…

Astrophysics of Galaxies · Physics 2023-05-10 Allison Smith , D. Anish Roshi

We resolve 182 individual giant molecular clouds (GMCs) larger than 2.5 $\times$ 10$^{5}$ \Msun in the inner disks of five large nearby spiral galaxies (NGC 2403, NGC 3031, NGC 4736, NGC 4826, and NGC 6946) to create the largest such sample…

Using the QUIJOTE line survey in the 32.0-50.4 GHz range, we report the discovery of the molecule CH2CCHC4H towards the prestellar cold core TMC-1 in the Taurus region. We also present a rigorous detection of CH2CCHC3N, along with its…

Astrophysics of Galaxies · Physics 2022-07-13 R. Fuentetaja , C. Cabezas , M. Agundez , B. Tercero , N. Marcelino , J. R. Pardo , P. de Vicente , J. Cernicharo

We present a theoretical investigation of CN and HCN molecule formation in dense interstellar clouds. We study the gas-phase CN and HCN production efficiencies from the outer photon-dominated regions (PDRs) into the opaque cosmic-ray…

Astrophysics · Physics 2009-11-13 Gai I. Boger , Amiel Sternberg

Interpretations of exoplanetary transmission spectra have been undermined by apparent obscuration due to clouds/hazes. Debate rages on whether weak H$_2$O features seen in exoplanet spectra are due to clouds or inherently depleted oxygen.…

Earth and Planetary Astrophysics · Physics 2017-05-29 Ryan J. MacDonald , Nikku Madhusudhan

Diffuse and translucent molecular clouds fill a vast majority of the interstellar space in the galactic disk being thus the most typical objects of the Interstellar Medium (ISM). Recent advances in observational techniques of modern optical…

Solar and Stellar Astrophysics · Physics 2013-04-18 T. Weselak

Some well-studied Herbig Haro objects have associated with them one or more cold, dense, and quiescent clumps of gas. We propose that such clumps near an HH object can be used as a general measure of clumpiness in the molecular cloud that…

Astrophysics of Galaxies · Physics 2015-05-14 W. Whyatt , J. M. Girart , S. Viti , R. Estalella , D. A. Williams

We studied the abundance of HCN, H13CN, and HN13C in a sample of prestellar cores, in order to search for species associated with high density gas. We used the IRAM 30m radiotelescope to observe along the major and the minor axes of L1498,…

Astrophysics of Galaxies · Physics 2015-05-30 M. Padovani , C. M. Walmsley , M. Tafalla , P. Hily-Blant , G. Pineau des Forêts

Aims. We model a diffuse molecular cloud present along the line of sight to the star HD 102065. We compare our modeling with observations to test our understanding of physical conditions and chemistry in diffuse molecular clouds. Methods.…

We report a systematic study of all known methyl carbon chains toward TMC-1 using the second data release of the GOTHAM survey, as well as a search for larger species. Using Markov-Chain Monte Carlo simulations and spectral line stacking of…

Nowadays there are several observational studies about the 13CO/C18O abundance ratio (X) towards nearby molecular clouds. These works give observational support to the C18O selective photodissociation due to the interaction between the FUV…

Astrophysics of Galaxies · Physics 2020-01-08 M. B. Areal , S. Paron , M. E. Ortega , L. Duvidovich

Using the Large Millimeter Telescope and the SEQUOIA 3~mm focal plane array, we have searched for molecular line emission from two atomic clouds associated with the Fermi Bubble of the Milky Way. Neither 12CO nor 13CO J=1-0 emission is…

Astrophysics of Galaxies · Physics 2025-03-12 M. Heyer , E. Di Teodoro , L. Loinard , F. J. Lockman , N. M. McClure-Griffiths , Q. D. Wang