Gravity or turbulence? - II. Evolving column density probability distribution functions in molecular clouds
نویسندگان
چکیده
منابع مشابه
Column Density Probability Distribution Functions in Turbulent Molecular Clouds: A Comparison between Theory and Observations
The one-point statistics of column density distributions of turbulent molecular cloud models are investigated and compared with observations. In agreement with the observations, the number N of pixels with surface density Σ is distributed exponentially N(Σ) ∼ exp(−Σ/Σ0) in models of driven compressible supersonic turbulence. However, in contrast to the observations, the exponential slope define...
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We use the COMPLETE Survey’s observations of the Perseus star-forming region to assess and intercompare three methods for measuring column density in molecular clouds: near-infrared extinction mapping; thermal emission mapping in the far-IR; and mapping the intensity of CO isotopologues. Overall, the structures shown by all three tracers are morphologically similar, but important differences ex...
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We revisit the origin of Larson’s scaling relations, which describe the structure and kinematics of molecular clouds, based on recent observations and large-scale simulations of supersonic turbulence. Using dimensional analysis, we first show that the slopes in both linewidth–size and mass–size correlations observed on scales 0.1 − 50 pc can be explained by a simple conceptual theory of compres...
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We study the probability distribution function (PDF) of the mass density in simulations of supersonic turbulence with properties appropriate for molecular clouds. For this study we use Athena, a new higher-order Godunov code. We find there are surprisingly similar relationships between the mean of the time-averaged PDF and the turbulent Mach number for driven hydrodynamic and strong-field MHD t...
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The formation of stars is inextricably linked to the structure of their parental molecular clouds. Here we take a number of nearby giant molecular clouds (GMCs) and analyse their column density and mass distributions. This investigation is based on four new all-sky median colour excess extinction maps determined from 2MASS. The four maps span a range of spatial resolution of a factor of eight. ...
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ژورنال
عنوان ژورنال: Monthly Notices of the Royal Astronomical Society
سال: 2011
ISSN: 0035-8711
DOI: 10.1111/j.1365-2966.2011.19141.x