English
Related papers

Related papers: The Column Density Probability Density Function of…

200 papers

The probability density function (PDF) of the logarithmic density contrast, $s=\ln (\rho/\rho_0)$, with gas density $\rho$ and mean density $\rho_0$, for hydrodynamical supersonic turbulence is well-known to have significant non-Gaussian…

Astrophysics of Galaxies · Physics 2022-11-16 James R. Beattie , Philip Mocz , Christoph Federrath , Ralf S. Klessen

We present a number of statistical tools for obtaining studying turbulence in molecular clouds and diffuse interstellar medium. For our tests we used of three-dimensional 512 cube compressible MHD isothermal simulations performed for…

Astrophysics · Physics 2011-02-11 Blakesley Burkhart , D. Falceta-Goncalves , G. Kowal , A. Lazarian

In this paper, we study the statistical evolution of the large-scale structure (LSS), focusing on the joint probability distribution function (PDF) of the coarse-grained cosmic field and its role in constructing effective dynamics. As the…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-20 Xin Wang

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

We calculate the one-point probability distribution function (PDF) for cosmic density in non-linear regime of the gravitational evolution. Under the local approximation that the evolution of cosmic fluid fields can be characterized by the…

Astrophysics · Physics 2009-11-10 Yasuhiro Ohta , Issha Kayo , Atsushi Taruya

(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…

Astrophysics · Physics 2007-11-07 David A. Tilley , Ralph E. Pudritz

The probability density function (PDF) of velocity fluctuations is studied experimentally for grid turbulence in a systematical manner. At small distances from the grid, where the turbulence is still developing, the PDF is sub-Gaussian. At…

Fluid Dynamics · Physics 2009-11-07 H. Mouri , M. Takaoka , A. Hori , Y. Kawashima

Study of parton distribution functions (PDFs) has led to a finer cognisance of the structure of partons in hadrons and the proton structure functions in deep inelastic scattering (DIS). PDFs are instrumental in predicting results for most…

High Energy Physics - Phenomenology · Physics 2025-10-02 Akbari Jahan , Diptimonta Neog

The molecular component of the Galaxy is comprised of turbulent, magnetized clouds, many of which are self-gravitating and form stars. To understand how these clouds' evolution may depend on their level of turbulence, mean magnetization,…

Astrophysics · Physics 2009-10-31 Eve C. Ostriker , Charles F. Gammie , James M. Stone

We examine how well the physical properties of clumps in turbulent molecular clouds can be determined by measurements of observed clump structures. We compare simulated observations of three-dimensional numerical models of isothermal,…

Astrophysics · Physics 2009-11-07 Javier Ballesteros-Paredes , Mordecai-M. Mac Low

The interstellar medium of galaxies is governed by supersonic turbulence, which likely controls the star formation rate (SFR) and the initial mass function (IMF). Interstellar turbulence is non-universal, with a wide range of Mach numbers,…

Astrophysics of Galaxies · Physics 2015-03-13 Christoph Federrath , Supratik Banerjee

Star formation is intimately linked to the dynamical evolution of molecular clouds. Turbulent fragmentation determines where and when protostellar cores form, and how they contract and grow in mass via accretion from the surrounding cloud…

Astrophysics · Physics 2007-05-23 Ralf Klessen

We present a general framework to treat the evolution of one-point probability distribution function (PDF) for cosmic density $\delta$ and velocity-divergence fields $\theta$. In particular, we derive an evolution equation for the one-point…

Astrophysics · Physics 2009-11-07 Yasuhiro Ohta , Issha Kayo , Atsushi Taruya

The compressibility of molecular cloud (MC) turbulence plays a crucial role in star formation models, because it controls the amplitude and distribution of density fluctuations. The relation between the compressive ratio (the ratio of…

Astrophysics of Galaxies · Physics 2016-07-06 Liubin Pan , Paolo Padoan , Troels Haugbolle , Aake Nordlund

To complement the optical absorption-line survey of diffuse molecular gas in Paper I, we obtained and analyzed far ultraviolet H$_2$ and CO data on lines of sight toward stars in Cep OB2 and Cep OB3. Possible correlations between column…

Astrophysics · Physics 2009-11-13 K. Pan , S. R. Federman , Y. Sheffer , B. -G. Andersson

{It is well established that the atomic interstellar hydrogen is filling the galaxies and constitutes the building blocks of molecular clouds.} {To understand the formation and the evolution of molecular clouds, it is necessary to…

Astrophysics of Galaxies · Physics 2015-05-14 E. Audit , P. Hennebelle

We investigate the behavior of the magnetic pressure, $b^2$, in fully turbulent MHD flows in ``1+2/3'' dimensions by means of its effect on the probability density function (PDF) of the density field. We start by reviewing our previous…

Astrophysics · Physics 2007-05-23 Enrique Vazquez-Semadeni , Thierry Passot

This paper exposes a novel exploratory formalism, which end goal is the numerical simulation of the dynamics of a cloud of particles weakly or strongly coupled with a turbulent fluid. Giventhe large panel of expertise of the list of…

Analysis of PDEs · Mathematics 2019-10-21 Ludovic Goudenège , Adam Larat , Julie Llobell , Marc Massot , David Mercier , Olivier Thomine , Aymeric Vié

We present three numerical simulations of randomly driven, isothermal, non-magnetic, self-gravitating turbulence with different rms Mach numbers Ms and physical sizes L, but approximately the same value of the virial parameter, alpha approx…

We present a simple, yet powerful column density diagnostic for plasmas enabled by X-ray microcalorimeter observations. With the recent developments of the spectral simulation code Cloudy, inspired by the high spectral resolution of the…

High Energy Astrophysical Phenomena · Physics 2025-02-19 Chamani M. Gunasekera , Peter A. M. van Hoof , Masahiro Tsujimoto , Gary J. Ferland