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Related papers: The Density Variance Mach Number Relation in the T…

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We examine the relation between the density variance and the mean-square Mach number in supersonic, isothermal turbulence, assumed in several recent analytic models of the star formation process. From a series of calculations of supersonic,…

Astrophysics of Galaxies · Physics 2015-05-20 Daniel J. Price , Christoph Federrath , Christopher M. Brunt

It is widely accepted that supersonic, magnetised turbulence plays a fundamental role for star formation in molecular clouds. It produces the initial dense gas seeds out of which new stars can form. However, the exact relation between gas…

Astrophysics of Galaxies · Physics 2012-04-13 F. Z. Molina , S. C. O. Glover , C. Federrath , R. S. Klessen

[abridged] We determine the relationship between turbulence energy and gas density variance for 15 molecular clouds in the Solar neighbourhood. We use the linewidths of the CO molecule as the probe of the turbulence energy (sonic Mach…

Astrophysics of Galaxies · Physics 2017-12-06 Jouni Kainulainen , Christoph Federrath

(abridged) We report a study of the relation between dust and gas over a 100deg^2 area in the Taurus molecular cloud. We compare the H2 column density derived from dust extinction with the CO column density derived from the 12CO and 13CO J=…

Astrophysics of Galaxies · Physics 2010-09-07 Jorge L. Pineda , Paul F. Goldsmith , Nicholas Chapman , Ronald L. Snell , Di Li , Laurent Cambresy , Chris Brunt

Although there are a wealth of column density tracers for both the molecular and diffuse interstellar medium, there are very few observational studies investigating the relationship between the density variance ($\sigma^2$) and the sonic…

Astrophysics of Galaxies · Physics 2015-06-05 Blakesley Burkhart , A. Lazarian

Maps of estimated dust column density in molecular clouds are usually assumed to reliably trace the total gas column density structure. In this work we present results showing a clear discrepancy between the dust and the gas distribution in…

We report the results of a 100 square degree survey of the Taurus Molecular Cloud region in the J = 1-0 transition of 12CO and 13CO. The image of the cloud in each velocity channel includes ~ 3 million Nyquist sampled pixels on a 20" grid.…

Astrophysics · Physics 2009-12-08 Paul F. Goldsmith , Mark Heyer , Gopal Narayanan , Ronald Snell , Di Li , Chris Brunt

Molecular clouds are supersonically turbulent. This turbulence governs the initial mass function and the star formation rate. In order to understand the details of star formation, it is therefore essential to understand the properties of…

Astrophysics of Galaxies · Physics 2015-06-17 Adam Ginsburg , Christoph Federrath , Jeremy Darling

We study the magnetic field to density ($B-\rho$) relation in turbulent molecular clouds with dynamically important magnetic fields using nonideal three-dimensional magnetohydrodynamic simulations. Our simulations show that there is a…

Astrophysics of Galaxies · Physics 2022-03-30 Sayantan Auddy , Shantanu Basu , Takahiro Kudoh

Supersonic turbulence is a key player in controlling the structure and star formation potential of molecular clouds (MCs). The three-dimensional (3D) turbulent Mach number, $\mathcal{M}$, allows us to predict the rate of star formation.…

Astrophysics of Galaxies · Physics 2019-07-17 James R. Beattie , Christoph Federrath , Ralf S. Klessen , Nicola Schneider

Shocks form the basis of our understanding for the density and velocity statistics of supersonic turbulent flows, such as those found in the cool interstellar medium (ISM). The variance of the density field, $\sigma^2_{\rho/\rho_0}$, is of…

Astrophysics of Galaxies · Physics 2021-04-28 James R. Beattie , Philip Mocz , Christoph Federrath , Ralf S. Klessen

Constraining the physical and chemical evolution of molecular clouds is essential to our understanding of star formation. These investigations often necessitate knowledge of some local representative number density of the gas along the line…

Astrophysics of Galaxies · Physics 2025-04-02 Brandt A. L. Gaches , Michael Y. Grudić

Studying the atomic-to-molecular transition is essential for understanding the evolution of interstellar medium. The linear edge of Taurus molecular cloud, clearly identified in the $^{13}$CO(1-0) intensity map, serves as an ideal site for…

Astrophysics of Galaxies · Physics 2025-04-03 Ningyu Tang , Feihang Miao , Gan Luo , Di Li , Junzhi Wang , Fujun Du , Donghong Wu , Shu Liu

Supersonic turbulence is a large reservoir of suprathermal energy in the interstellar medium. Its dissipation, because it is intermittent in space and time, can deeply modify the chemistry of the gas. We further explore a hybrid method to…

Astrophysics of Galaxies · Physics 2009-11-13 Benjamin Godard , Edith Falgarone , Guillaume Pineau Des Forêts

We study four lines of sight that probe the transition from diffuse molecular gas to molecular cloud material in Taurus. Measurements of atomic and molecular absorption are used to infer the distribution of species and the physical…

The probability density function (PDF) of the gas density in subsonic and supersonic, isothermal, driven turbulence is analyzed with a systematic set of hydrodynamical grid simulations with resolutions up to 1024^3 cells. We performed a…

Solar and Stellar Astrophysics · Physics 2014-11-27 Lukas Konstandin , Philipp Girichidis , Christoph Federrath , Ralf S. Klessen

We determine the physical properties and turbulence driving mode of molecular clouds formed in numerical simulations of a Milky Way-type disc galaxy with parsec-scale resolution. The clouds form through gravitational fragmentation of the…

Astrophysics of Galaxies · Physics 2017-05-31 Keitaro Jin , Diane M. Salim , Christoph Federrath , Elizabeth J. Tasker , Asao Habe , Jouni T. Kainulainen

We propose a model for the density statistics in supersonic turbulence, which play a crucial role in star-formation and the physics of the interstellar medium (ISM). Motivated by [Hopkins, MNRAS, 430, 1880 (2013)], the model considers the…

Astrophysics of Galaxies · Physics 2017-08-30 Jonathan Squire , Philip F. Hopkins

We aim to better understand how the spatial structure of molecular clouds is governed by turbulence. For that, we study the large-scale spatial distribution of low density molecular gas and search for characteristic length scales. We employ…

Astrophysics of Galaxies · Physics 2015-05-18 N. Schneider , S. Bontemps , R. Simon , V. Ossenkopf , C. Federrath , R. Klessen , F. Motte , P. Andre , J. Stutzki , C. Brunt

We study how the estimation of the sonic Mach number ($M_s$) from $^{13}$CO linewidths relates to the actual 3D sonic Mach number. For this purpose we analyze MHD simulations which include post-processing to take radiative transfer effects…

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