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相关论文: Mass-density relationship in molecular cloud clump…

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We derive the mass function of condensations (clumps) which were formed through a turbulent cascade over a range of spatial scales $L\le20$ pc during early, predominantly turbulent evolution of a molecular cloud. The approach rests upon the…

太阳与恒星天体物理 · 物理学 2015-06-04 Sava Donkov , Todor V. Veltchev , Ralf S. Klessen

We introduce the concept of a class of equivalence of molecular clouds represented by an abstract spherically symmetric, isotropic object. This object is described by use of abstract scales in respect to a given mass density distribution.…

星系天体物理 · 物理学 2017-01-18 Sava Donkov , Todor V. Veltchev , Ralf S. Klessen

Abridged: We study the properties of clumps formed in three-dimensional weakly magnetized magneto-hydrodynamic simulations of converging flows in the thermally bistable, warm neutral medium (WNM). We find that: (1) Similarly to the…

天体物理学 · 物理学 2015-05-13 Robi Banerjee , Enrique Vazquez-Semadeni , Patrick Hennebelle , Ralf Klessen

Using a sample of ten nearby (z< 0.15), relaxed galaxy clusters in the temperature range [2-9] keV, we have investigated the scaling relation between the mass at various density contrasts (delta=2500,1000,500,200) and the cluster…

天体物理学 · 物理学 2008-11-26 M. Arnaud , E. Pointecouteau , G. W. Pratt

We investigate how the properties of Galactic giant molecular clouds (GMCs) and their denser substructures (clumps) correlate with the local star formation rate. We trace clouds using the $^{12}$CO(3-2) transition, as observed by the CO…

星系天体物理 · 物理学 2019-09-04 Erika Zetterlund , Jason Glenn , Erik Rosolowsky

We present a model for describing the general structure of molecular clouds (MCs) at early evolutionary stages in terms of their mass-size relationship. Sizes are defined through threshold levels at which equipartitions between…

星系天体物理 · 物理学 2016-04-26 Todor V. Veltchev , Sava Donkov , Ralf S. Klessen

We have analyzed HCN(1-0) and CS(2-1) line profiles obtained with high signal-to-noise ratios toward distinct positions in three selected objects in order to search for small-scale structure in molecular cloud cores associated with regions…

星系天体物理 · 物理学 2011-08-31 L. E. Pirogov , I. I. Zinchenko

We analyze the physical properties and energy balance of density enhancements in two SPH simulations of the formation, evolution, and collapse of giant molecular clouds. In the simulations, no feedback is included, so all motions are due…

Spatial association of clumps from different tracers turns out to be a valuable tool to determine the physical properties of molecular clouds. It provides a reliable estimate for the $X$-factors, serves to trace the density of clumps seen…

We investigate physical properties of molecular clouds in disc galaxies with different morphology: a galaxy without prominent structure, a spiral barred galaxy and a galaxy with flocculent structure. Our $N$-body/hydrodynamical simulations…

星系天体物理 · 物理学 2016-03-02 S. A. Khoperskov , E. O. Vasiliev , D. A. Ladeyschikov , A. M. Sobolev , A. V. Khoperskov

We study the physical properties derived from interstellar cloud complexes having a fractal structure. We first generate fractal clouds with a given fractal dimension and associate each clump with a maximum in the resulting density field.…

天体物理学 · 物理学 2008-11-26 Nestor Sanchez , Emilio J. Alfaro , Enrique Perez

The most accurate measurements of magnetic fields in star-forming gas are based on the Zeeman observations analyzed by Crutcher et al. (2010). We show that their finding that the 3D magnetic field scales approximately as density$^{0.65}$…

星系天体物理 · 物理学 2015-08-06 Pak Shing Li , Christopher F. McKee , Richard I. Klein

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…

星系天体物理 · 物理学 2015-05-18 D. Froebrich , J. Rowles

The mass function of galaxies and clusters of galaxies can be derived observationally based on different types of observations. In this study we test if these observations can be combined to a consistent picture which is also in accord with…

星系天体物理 · 物理学 2019-10-24 Masataka Fukugita , Hans Böhringer

(Abridged) We present a series of decaying turbulence simulations that represent a cluster-forming clump within a molecular cloud, investigating the role of magnetic fields on the formation of potential star-forming cores. We present an…

天体物理学 · 物理学 2007-11-07 David A. Tilley , Ralph E. Pudritz

Observations reveal concentrations of molecular line emission on the sky, called ``clumps,'' in dense, star-forming molecular clouds. These clumps are believed to be the eventual sites of star formation. We study the three-dimensional…

天体物理学 · 物理学 2009-11-07 C. F. Gammie , Y. -T. Lin , J. M. Stone , E. C. Ostriker

The outer Galaxy presents an optimal setting for investigating molecular clouds and star formation in environments with low metallicity. A total of 72 Galactic edge clouds were surveyed using the CO\,(2--1) line with the IRAM\,30\,m…

The statistical approach for derivation of the clump mass function (ClMF) developed by Donkov, Veltchev & Klessen is put to observational test through comparison with mass distributions of clumps from molecular emission and dust continuum…

星系天体物理 · 物理学 2015-06-15 Todor V. Veltchev , Sava Donkov , 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 report the results of high-resolution (~0.2 pc) CO(1-0) and CS(2-1) observations of the central regions of three star-forming molecular clouds in the far-outer Galaxy (~16 kpc from the Galactic Center): WB89 85 (Sh 2-127), WB89 380, and…

天体物理学 · 物理学 2016-08-30 J. Brand , J. G. A. Wouterloot , A. L. Rudolph , E. J. de Geus
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