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Related papers: Revisiting the Velocity Dispersion-Size Relation i…

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The cloud-scale density, velocity dispersion, and gravitational boundedness of the interstellar medium (ISM) vary within and among galaxies. In turbulent models, these properties play key roles in the ability of gas to form stars. New high…

This paper is aimed at exploring implications of velocity dispersion scalings on high-mass star formation in molecular clouds, including the scalings of Larson's linewidth--size ($\sigma$--$R$) and ratio--mass surface density…

Astrophysics of Galaxies · Physics 2024-05-09 An-Xu Luo , Hong-Li Liu , Sheng-Li Qin , Dong-Ting Yang , Sirong Pan

The linewidth (sigma) - size (R) relationship has been extensively measured and analysed, in both the local ISM and in nearby normal galaxies. Generally, a power-law describes the relationship well with an index ranging from 0.2-0.6, now…

Astrophysics of Galaxies · Physics 2015-06-05 Rahul Shetty , Christopher N. Beaumont , Michael G. Burton , Brandon C. Kelly , Ralf S. Klessen

Different studies have reported a power-law mass-size relation $M \propto R^q$ for ensembles of molecular clouds. In the case of nearby clouds, the index of the power-law $q$ is close to 2. However, for clouds spread all over the Galaxy,…

We present results from a statistical study of clouds in two-dimensional numerical simulations of the interstellar medium. The clouds in the simulations exhibit a differential mass spectrum $dN(M)/dM \sim M^{-1.44 \pm 0.1}$ and a velocity…

Astrophysics · Physics 2009-10-28 E. Vazquez-Semadeni , J. Ballesteros-Paredes , L. F. Rodriguez

We discuss the nature of the velocity dispersion vs. size relation for molecular clouds. In particular, we add to previous observational results showing that the velocity dispersions in molecular clouds and cores are not purely functions of…

We present a systematic analysis of the velocity structure functions (VSFs) of 167 molecular clouds with angular sizes greater than $\sim$176 arcmin$^2$ in three sectors of the Galactic mid-plane. We calculated the 1st- to 3rd-order VSFs…

The velocity dispersion-size relation ($\sigma_{\rm v}\sim R^{\beta}$) is a crucial indicator of the dynamic properties of interstellar gas, where the slope is considered as $\beta \sim 0.5$. Recent observations reveal a steep velocity…

Astrophysics of Galaxies · Physics 2025-05-14 Yi-Heng Xie , Guang-Xing Li

We measure the velocity dispersion, $\sigma$, and surface density, $\Sigma$, of the molecular gas in nearby galaxies from CO spectral line cubes with spatial resolution $45$-$120$ pc, matched to the size of individual giant molecular…

The shape of the cold interstellar molecular gas is determined by several processes, including self-gravity, tidal force, turbulence, magnetic field, and galactic shear. Based on the 3D dust extinction map derived by Vergely et al., we…

Astrophysics of Galaxies · Physics 2024-08-27 Yi-Heng Xie , Guang-Xing Li , Bing-Qiu Chen

We discuss the estimation of galaxy correlation properties in several volume limited samples, in different sky regions, obtained from the Fourth Data Release of the Sloan Digital Sky Survey. The small scale properties are characterized…

Astrophysics · Physics 2009-03-19 Francesco Sylos Labini , Nickolay L. Vasilyev , Yurij V. Baryshev

We revisit the mass-size relation of molecular cloud structures based on the column density map of the Cygnus-X molecular cloud complex. We extract 135 column density peaks in Cygnus-X and analyze the column density distributions around…

Astrophysics of Galaxies · Physics 2022-05-18 Yuchen Xing , Keping Qiu

From a new perspective, we re-examine self-gravity and turbulence jointly, in hopes of understanding the physical basis for one of the most important empirical relations governing clouds in the interstellar medium (ISM), the Larson's…

Astrophysics of Galaxies · Physics 2021-01-13 Renyue Cen

Using hydrodynamical simulations of entire galactic discs similar to the Milky Way, reaching 4.6pc resolution, we study the origins of observed physical properties of giant molecular clouds (GMCs). We find that efficient stellar feedback is…

Astrophysics of Galaxies · Physics 2018-07-04 Kearn Grisdale , Oscar Agertz , Florent Renaud , Alessandro B. Romeo

Power law mass-size and linewidth-size correlations, two of "Larson's laws," are often studied to assess the dynamical state of clumps within molecular clouds. Using the result of a hydrodynamic simulation of a molecular cloud, we…

Astrophysics of Galaxies · Physics 2015-05-18 Rahul Shetty , David C. Collins , Jens Kauffmann , Alyssa A. Goodman , Erik W. Rosolowsky , Michael L. Norman

Recently reported variations in the typical physical properties of Galactic and extra-Galactic molecular clouds (MCs), and in their ability to form stars have been attributed to local variations in the magnitude of interstellar pressure.…

Astrophysics of Galaxies · Physics 2017-01-18 S. Anathpindika , A. Burkert , R. Kuiper

An analysis of large-area CO J=3-2 maps from the James Clerk Maxwell Telescope for 12 nearby spiral galaxies reveals low velocity dispersions in the molecular component of the interstellar medium. The three lowest luminosity galaxies show a…

The interstellar medium (ISM) reveals strongly inhomogeneous structures at every scale. These structures do not seem completely random since they obey certain power laws. Larson's law (\citeyear{Larson81}) $\sigma \propto R^{\delta}$ and…

Astrophysics · Physics 2009-10-31 Daniel Huber , Daniel Pfenniger

A statistical analysis is presented of the turbulent velocity structure in the Orion Molecular Cloud at scales ranging from 70 AU to 30000 AU. Results are based on IR Fabry-Perot interferometric observations of shock and photon-excited H2…

Astrophysics · Physics 2016-08-30 M. Gustafsson , D. Field , J. L. Lemaire , F. P. Pijpers

The evolution of the molecular interstellar medium is controlled by processes such as turbulence, gravity, stellar feedback, and Galactic shear. AL a part of the ISM-6D https://gxli.github.io/ISM-6D/ project, using Gaia astrometric…

Astrophysics of Galaxies · Physics 2022-04-13 Ji-Xuan Zhou , Guang-Xing Li , Bing-Qiu Chen
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