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We apply gravity-based and density-based methods to identify clouds in numerical simulations of the star-forming, three-phase interstellar medium (ISM), and compare their properties and their global correlation with the star formation rate…

Astrophysics of Galaxies · Physics 2020-07-29 S. Alwin Mao , Eve C. Ostriker , Chang-Goo Kim

Analyzing the Galactic plane CO survey with the Nobeyama 45-m telescope, we compared the spectral column density (SCD) of H$_2$ calculated for $^{12}$CO line using the current conversion factor $X_{\rm CO}$ to that for $^{13}$CO line under…

Astrophysics of Galaxies · Physics 2020-07-22 Yoshiaki Sofue , Mikito Kohno

We perform numerical magnetohydrodynamic (MHD) simulations of the gravitational collapse and fragmentation of a cylindrical molecular cloud with the help of the FLASH code. The cloud collapses rapidly along its radius without any signs of…

Astrophysics of Galaxies · Physics 2024-05-15 I. M. Sultanov , S. A. Khaibrakhmanov

Observations suggest that filaments in molecular clouds can grow by mass accretion while forming cores via fragmentation. Here we present one of the first large sample studies of filament accretion using velocity gradient measurements of…

We suggest that molecular clouds can be formed on short time scales by compressions from large scale streams in the interstellar medium (ISM). In particular, we argue that the Taurus-Auriga complex, with filaments of 10-20 pc $\times$ 2-5…

Astrophysics · Physics 2010-04-06 Javier Ballesteros-Paredes , Lee Hartmann , Enrique Vazquez-Semadeni

Context: The large Coalsack dark cloud is one of the rare molecular clouds without clear signs of star formation. Aims: We investigate the dynamical properties of the gas within the Coalsack. Methods: The two highest extinction regions were…

Solar and Stellar Astrophysics · Physics 2015-05-28 H. Beuther , J. Kainulainen , Th. Henning , R. Plume , F. Heitsch

We present the first systematic study of the density structure of clouds found in a complete sample covering all major molecular clouds in the Central Molecular Zone (CMZ; inner $\sim{}200~\rm{}pc$) of the Milky Way. This is made possible…

The probability density functions (pdfs) of molecular line centroid velocity fluctuations and fluctuation differences at different spatial lags are estimated for several nearby molecular clouds with active internal star formation. The data…

Astrophysics · Physics 2009-10-31 M. S. Miesch , J. M. Scalo , J. Bally

We explore molecular cloud properties and the physics of CO transition lines in z >~ 6 Lyman-break galaxies and predict their CO fluxes using an analytic formalism built from global models of star formation in high-redshift galaxies that…

Cosmology and Nongalactic Astrophysics · Physics 2014-04-09 Joseph A. Muñoz , Steven R. Furlanetto

Dense molecular filaments are central to the star formation process, but the detailed manner in which they fragment into prestellar cores is not yet well understood. Here, we investigate the fragmentation properties and dynamical state of…

Solar and Stellar Astrophysics · Physics 2020-10-07 Guo Yin Zhang , Ph. Andre , A. Menshchikov , Ke Wang

(Abridged) Aims & Methods. A two-dimensional, semi-analytical model is presented that follows, for the first time, the chemical evolution from a collapsing molecular cloud (a pre-stellar core) to a protostar and circumstellar disk. The…

Solar and Stellar Astrophysics · Physics 2009-11-13 R. Visser , E. F. van Dishoeck , S. D. Doty , C. P. Dullemond

Stars form in the dense interiors of molecular clouds. The dynamics and physical properties of the atomic interstellar medium (ISM) set the conditions under which molecular clouds and eventually stars will form. It is, therefore, critical…

We have mapped cold atomic gas in 21cm line HI self-absorption (HISA) at arcminute resolution over more than 90% of the Milky Way's disk. To probe the formation of H2 clouds, we have compared our HISA distribution with CO J=1-0 line…

We have analysed the chemical and kinematic properties of the 20 and 50 km s$^{-1}$ molecular clouds in the Central Molecular Zone of the Milky Way Galaxy, as well as those of the molecular ridge bridging these two clouds. Our work has…

A giant star-forming region in a metal-poor dwarf galaxy has been observed in optical lines with the 10-m Gran Telescopio Canarias and in the emission line of CO(1-0) with the NOEMA mm-wave interferometer. The metallicity was determined to…

We study the relation between molecular gas and star formation in a volume-limited sample of 222 galaxies from the COLD GASS survey, with measurements of the CO(1-0) line from the IRAM 30m telescope. The galaxies are at redshifts…

The star-forming region N66, as a host of the majority of OB stars in the Small Magellanic Cloud, provides a unique opportunity to enhance our understanding of the triggers of high-mass star formation. We investigate the properties of the…

Astrophysics of Galaxies · Physics 2025-03-18 Batool Ilyasi , Naslim Neelamkodan , Kazuki Tokuda , Susmita Barman , Marta Sewilo , Hidetoshi Sano , Toshikazu Onishi

Supercritical gas filaments in molecular clouds host the dense cores in which new stars form. The mechanisms governing their formation and subsequent gas accretion remain poorly understood. In this study, we conduct a statistical analysis…

The results of spectral observations in the $\sim 84-92$ GHz frequency range of six objects in the southern sky containing dense cores and associated with regions of massive stars and star clusters formation are presented. The observations…

Astrophysics of Galaxies · Physics 2024-03-06 L. E. Pirogov , P. M. Zemlyanukha , E. M. Dombek , M. A. Voronkov

We present a study of the compact blister HII region BFS 10 and its highly filamentary molecular cloud. We utilize 12CO observations from the Five College Radio Astronomy Observatory to determine the distance, size, mass, and velocity…

Astrophysics of Galaxies · Physics 2022-09-14 Nicholas Larose , C. R. Kerton