English
Related papers

Related papers: Extraction of a second power-law tail of the densi…

200 papers

Using a non-perturbative method developed in a previous article (paper II) we investigate the tails of the probability distribution $P(\rho_R)$ of the overdensity within spherical cells. We show that our results for the low-density tail of…

Astrophysics · Physics 2009-11-06 P. Valageas

A simple model accounting for the ejection of heavy particles from the vortical structures of a turbulent flow is introduced. This model involves a space and time discretization of the dynamics and depends on only two parameters: the…

Chaotic Dynamics · Physics 2009-11-13 Jeremie Bec , Raphael Chetrite

We derive an analytic expression for the transitional column density value ($s_t$) between the lognormal and power-law form of the probability distribution function (PDF) in star-forming molecular clouds. Our expression for $s_t$ depends on…

Astrophysics of Galaxies · Physics 2016-12-28 Blakesley Burkhart , Kye Stalpes , David Collins

The probability distribution function (PDF) of the mass surface density is an essential characteristic of the structure of molecular clouds or the interstellar medium in general. Observations of the PDF of molecular clouds indicate a…

Astrophysics of Galaxies · Physics 2015-06-18 Joerg Fischera

The possibility to detect cosmological signals from the post-recombination Universe is one of the main aims of modern cosmology. In a previous paper we emphasized the role that elastic resonant scattering through LiH molecules can have in…

Astrophysics · Physics 2008-11-26 R. Maoli , V. Ferrucci , F. Melchiorri , M. Signore , D. Tosti

Curve of growth analysis, applied to the Lyman series absorption ratios deduced in our previous paper, yields a measurement of the logarithmic slope of distribution of \Lya\ clouds in column density $N$. The observed exponential…

Astrophysics · Physics 2009-10-22 William H. Press , George B. Rybicki

Column density (N) PDFs serve as a powerful tool to characterize the physical processes that influence the structure of molecular clouds. Star-forming clouds can best be characterized by lognormal PDFs for the lower N range and a power-law…

Power-law probability distributions are widely used to model extreme statistical events in complex systems, with applications to a vast array of natural phenomena ranging from earthquakes to stock market crashes to pandemics. We show that…

Quantum Physics · Physics 2026-04-08 Wai-Keong Mok

Turbulence is essential for understanding the structure and dynamics of molecular clouds and star-forming regions. There is a need for adequate tools to describe and characterize the properties of turbulent flows. One-point probability…

Astrophysics · Physics 2008-11-26 Ralf S. Klessen

Using both analytic and numerical methods, we study the radial growth probability distribution $P(r,M)$ for large scale off lattice diffusion limited aggregation (DLA) clusters. If the form of $P(r,M)$ is a Gaussian, we show analytically…

Condensed Matter · Physics 2009-10-22 Peter Ossadnik , Jysoo Lee

(Abridged) We discuss the probability distribution function (PDF) of column density resulting from density fields with lognormal PDFs, applicable to isothermal gas (e.g., probably molecular clouds). We suggest that a ``decorrelation…

Astrophysics · Physics 2009-11-06 Enrique Vazquez-Semadeni , Nieves Garcia

Observational investigations of the abundance of massive precursors of local galaxy clusters ("proto-clusters") allow us to test the growth of density perturbations, to constrain cosmological parameters that control it, to test the theory…

Astrophysics of Galaxies · Physics 2017-07-26 M. Negrello , J. Gonzalez-Nuevo , G. De Zotti , M. Bonato , Z. -Y. Cai , D. Clements , L. Danese , H. Dole , J. Greenslade , A. Lapi , L. Montier

The evolution of molecular interstellar clouds is a complex, multi-scale process. The power-law density exponent describes the steepness of density profiles, and it has been used to characterize the density structures of the clouds yet its…

Astrophysics of Galaxies · Physics 2022-05-09 Guang-Xing Li , Ji-Xuan Zhou

The isothermal dynamical evolution of a clumpy and turbulent molecular cloud region and its fragmentation into a protostellar cluster is investigated numerically. The effect of different initial density and velocity distributions, generated…

Astrophysics · Physics 2008-11-26 Ralf S. Klessen , Andreas Burkert

Distinguishing power-law distributions from other heavy-tailed distributions is challenging, and this task is often further complicated by subsampling effects. In this work, we evaluate the performance of two commonly used methods for…

Data Analysis, Statistics and Probability · Physics 2024-05-09 Silja Sormunen , Lasse Leskelä , Jari Saramäki

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…

Astrophysics of Galaxies · Physics 2015-06-15 Todor V. Veltchev , Sava Donkov , Ralf S. Klessen

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…

Astrophysics of Galaxies · Physics 2015-05-18 D. Froebrich , J. Rowles

We present a new method for estimating the H2 cooling rate in the optically thick regime in simulations of primordial star formation. Our new approach is based on the TreeCol algorithm, which projects matter distributions onto a spherical…

Solar and Stellar Astrophysics · Physics 2015-05-05 Tilman Hartwig , Paul C. Clark , Simon C. O. Glover , Ralf S. Klessen , Mei Sasaki

Over the last few decades power law distributions have been suggested as forming generative mechanisms in a variety of disparate fields, such as, astrophysics, criminology and database curation. However, fitting these heavy tailed…

Computation · Statistics 2014-08-26 Colin S. Gillespie