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Related papers: CH$_3$OH as a User-Friendly Density Probe: Calibra…

200 papers

We present Green Bank Telescope (GBT) observations of the 3(12)-3(13) (29 GHz) and 4(13)-4(14) (48 GHz) transitions of the H2CO molecule toward a sample of 23 well-studied star-forming regions. Analysis of the relative intensities of these…

Astrophysics of Galaxies · Physics 2015-05-30 Patrick I. McCauley , Jeffrey G. Mangum , Alwyn Wootten

Star-forming regions host a large and evolving suite of molecular species. Molecular transition lines, particularly of complex molecules, can reveal the physical and dynamical environment of star formation. We aim to study the large-scale…

Astrophysics of Galaxies · Physics 2025-06-04 P. Freeman , S. Bottinelli , R. Plume , E. Caux , B. Mookerjea

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

Spectral line surveys reveal rich molecular reservoirs in G331.512-0.103, a compact radio source in the center of an energetic molecular outflow. In this first work, we analyse the physical conditions of the source by means of CH$_3$OH and…

The temperature is a central parameter affecting the chemical and physical properties of dense cores of interstellar clouds and their evolution to star formation. The chemistry and the dust properties are temperature dependent and the…

Astrophysics of Galaxies · Physics 2015-06-03 M. Juvela , J. Harju , N. Ysard , T. Lunttila

OB star clusters originate from parsec-scale massive molecular clumps. We aim to understand the evolution of temperature and density structures on the intermediate-scale ($\lesssim$0.1-1 pc) extended gas of massive clumps. We performed…

Galaxy formation depends on a complex interplay between gravitational collapse, gas accretion, merging, and feedback processes. Yet, after many decades of investigation, these concepts are poorly understood. This paper presents the argument…

We propose a methodology to perform a self-consistent analysis of the physical properties of the emitting gas of HII galaxies adequate to the data that can be obtained with the XXI century technology. This methodology requires the…

Astrophysics of Galaxies · Physics 2009-01-21 G. F. Hagele , A. I. Diaz , E. Terlevich , E. Perez-Montero , R. Terlevich , M. V. Cardaci

This paper presents the third in a series of single-dish studies of molecular abundances in the envelopes around a large sample of 18 low-mass pre- and protostellar objects. It focuses on typical grain mantle products and organic molecules,…

Astrophysics · Physics 2009-11-10 J. K. Jorgensen , F. L. Schoeier , E. F. van Dishoeck

We conducted observations of multiple HC3N (J = 10-9, 12-11, and 16-15) lines and the N2H+ (J = 1-0) line toward a large sample of 61 ultracompact (UC) H II regions, through the Institutde Radioastronomie Millmetrique 30 m and the Arizona…

Astrophysics of Galaxies · Physics 2023-02-21 Y. X. Wang , J. S. Zhang , H. Z. Yu , Y. Wang , Y. T. Yan , J. L. Chen , J. Y. Zhao , Y. P. Zou

We have introduced a new method of estimating the electron temperature and density of H II regions by using single dish observations. In this method, multiple hydrogen radio recombination lines of different bands are computed under the…

Solar and Stellar Astrophysics · Physics 2019-11-14 F. -Y. Zhu , Q. -F. Zhu , J. -Z. Wang , J. -S Zhang

We present a comparative study of physical properties derived from gas and dust emission in a sample of 1068 dense Galactic clumps. The sources are selected from the crossmatch of the Hi-GAL survey with 16 catalogues of NH$_3$ line emission…

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…

With a goal toward deriving the physical conditions in external galaxies, we present a survey of formaldehyde (H2CO) and ammonia (NH3) emission and absorption in a sample of starburst galaxies using the Green Bank Telescope. By extending…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Jeffrey G. Mangum , Jeremy Darling , Karl M. Menten , Christian Henkel , Meredith MacGregor

The H2O Southern Galactic Plane Survey (HOPS) has mapped a 100 degree strip of the Galactic plane (-70deg > l > 30deg, |b| < 0.5deg) using the 22-m Mopra antenna at 12-mm wavelengths. Observations were conducted in on-the-fly mode using the…

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…

Astrophysics of Galaxies · Physics 2023-10-11 F. D. Priestley , P. C. Clark , S. C. O. Glover , S. E. Ragan , O. Fehér , L. R. Prole , R. S. Klessen

We recently reported a population of protostellar candidates in the 20 km s$^{-1}$ cloud in the Central Molecular Zone of the Milky Way, traced by H$_2$O masers in gravitationally bound dense cores. In this paper, we report…

(abridged) In this work we have a closer look at the gas content or fraction and the associated star formation rate in main sequence and starburst galaxies at z=0 and z~1-2 by applying an analytical model of galactic clumpy gas disks to…

Astrophysics of Galaxies · Physics 2017-06-28 B. Vollmer , P. Gratier , J. Braine , C. Bot

The star forming processes strongly influence the ISM chemistry. Nowadays, there are available many high-quality databases at millimeter wavelengths. Using them, it is possible to carry out studies that review and deepen previous results.…

Astrophysics of Galaxies · Physics 2023-10-16 N. C. Martinez , S. Paron
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