Skip to main content

We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.

Close cookie message
Cancel
×
×
Home
  • Home
Chapter
  • Get access
    Buy the print book
    Check if you have access via personal or institutional login
    Log in Register Recommend to librarian
  • Cited by 71
  • Cited by
    Crossref Citations
    Crossref logo
    This (lowercase (translateProductType product.productType)) has been cited by the following publications. This list is generated based on data provided by CrossRef.
    Grudić, Michael Y Hopkins, Philip F Faucher-Giguère, Claude-André Quataert, Eliot Murray, Norman and Kereš, Dušan 2018. When feedback fails: the scaling and saturation of star formation efficiency. Monthly Notices of the Royal Astronomical Society, Vol. 475, Issue. 3, p. 3511.
    Egusa, Fumi Hirota, Akihiko Baba, Junichi and Muraoka, Kazuyuki 2018. Molecular Gas Properties in M83 from CO PDFs. The Astrophysical Journal, Vol. 854, Issue. 2, p. 90.
    Banda-Barragán, W. E. Federrath, C. Crocker, R. M. and Bicknell, G. V. 2018. Filament formation in wind–cloud interactions– II. Clouds with turbulent density, velocity, and magnetic fields. Monthly Notices of the Royal Astronomical Society, Vol. 473, Issue. 3, p. 3454.
    Elmegreen, Bruce G. 2018. On the Appearance of Thresholds in the Dynamical Model of Star Formation. The Astrophysical Journal, Vol. 854, Issue. 1, p. 16.
    Tanaka, Kunihiko Nagai, Makoto Kamegai, Kazuhisa Iino, Takahiro and Sakai, Takeshi 2018. HCN J = 4–3, HNC J = 1–0, H13CN J = 1–0, and HC3N J = 10–9 Maps of the Galactic Center Region. I. Spatially Resolved Measurements of Physical Conditions and Chemical Composition. The Astrophysical Journal Supplement Series, Vol. 236, Issue. 2, p. 40.
    Zhdankin, Vladimir Uzdensky, Dmitri A Werner, Gregory R and Begelman, Mitchell C 2018. Numerical investigation of kinetic turbulence in relativistic pair plasmas – I. Turbulence statistics. Monthly Notices of the Royal Astronomical Society, Vol. 474, Issue. 2, p. 2514.
    Hopkins, Philip F. and Conroy, Charlie 2017. Are the Formation and Abundances of Metal-poor Stars the Result of Dust Dynamics?. The Astrophysical Journal, Vol. 835, Issue. 2, p. 154.
    Bialy, Shmuel Burkhart, Blakesley and Sternberg, Amiel 2017. The H i-to-H2 Transition in a Turbulent Medium. The Astrophysical Journal, Vol. 843, Issue. 2, p. 92.
    Liptai, David Price, Daniel J. Wurster, James and Bate, Matthew R. 2017. Does turbulence determine the initial mass function?. Monthly Notices of the Royal Astronomical Society, Vol. 465, Issue. 1, p. 105.
    Jin, Keitaro Salim, Diane M. Federrath, Christoph Tasker, Elizabeth J. Habe, Asao and Kainulainen, Jouni T. 2017. On the effective turbulence driving mode of molecular clouds formed in disc galaxies. Monthly Notices of the Royal Astronomical Society, Vol. 469, Issue. 1, p. 383.
    Pan, Liubin Padoan, Paolo Haugbølle, Troels and Nordlund, Åke 2016. SUPERNOVA DRIVING. II. COMPRESSIVE RATIO IN MOLECULAR-CLOUD TURBULENCE. The Astrophysical Journal, Vol. 825, Issue. 1, p. 30.
    Ossenkopf-Okada, V. Csengeri, T. Schneider, N. Federrath, C. and Klessen, R. S. 2016. The reliability of observational measurements of column density probability distribution functions. Astronomy & Astrophysics, Vol. 590, Issue. , p. A104.
    Krčo, Marko and Goldsmith, Paul F. 2016. GEOMETRY-INDEPENDENT DETERMINATION OF RADIAL DENSITY DISTRIBUTIONS IN MOLECULAR CLOUD CORES AND OTHER ASTRONOMICAL OBJECTS. The Astrophysical Journal, Vol. 822, Issue. 1, p. 10.
    Federrath, Christoph 2016. Magnetic field amplification in turbulent astrophysical plasmas. Journal of Plasma Physics, Vol. 82, Issue. 06,
    Boyden, Ryan D. Koch, Eric W. Rosolowsky, Erik W. and Offner, Stella S. R. 2016. AN EXPLORATION OF THE STATISTICAL SIGNATURES OF STELLAR FEEDBACK. The Astrophysical Journal, Vol. 833, Issue. 2, p. 233.
    Yoon, Heesun Cho, Jungyeon and Kim, Jongsoo 2016. DENSITY-MAGNETIC FIELD CORRELATION IN MAGNETOHYDRODYNAMIC TURBULENCE DRIVEN BY DIFFERENT DRIVING SCHEMES WITH DIFFERENT CORRELATION TIMES. The Astrophysical Journal, Vol. 831, Issue. 1, p. 85.
    Tricco, Terrence S. Price, Daniel J. and Federrath, Christoph 2016. A comparison between grid and particle methods on the small-scale dynamo in magnetized supersonic turbulence. Monthly Notices of the Royal Astronomical Society, Vol. 461, Issue. 2, p. 1260.
    Kazandjian, M. V. Pelupessy, I. Meijerink, R. Israel, F. P. Coppola, C. M. Rosenberg, M. J. F. and Spaans, M. 2016. Constraining cloud parameters using high density gas tracers in galaxies. Astronomy & Astrophysics, Vol. 595, Issue. , p. A124.
    Ward, Rachel L. Wadsley, James and Sills, Alison 2014. Evolving molecular cloud structure and the column density probability distribution function. Monthly Notices of the Royal Astronomical Society, Vol. 445, Issue. 2, p. 1575.
    Fischera, Jörg 2014. On the probability distribution function of the mass surface density of molecular clouds. I. Astronomy & Astrophysics, Vol. 565, Issue. , p. A24.
    Download full list
    ×
  • Print publication year: 1999
  • Online publication date: August 2010

The Density PDFs of Supersonic Random Flows

    • By Åke Nordlund, Theoretical Astrophysics Center, Juliane Maries Vej 30, 2100 Copenhagen ø, Denmark, Astronomical Observatory / NBIfAFG, Juliane Maries Vej 30, 2100 Copenhagen ø, Denmark, Paolo Padoan, Instituto Nacional de Astrofisica, Optica y Electrónica, A.P. 51 y 216, Puebla 72000, México
  • Edited by Jose Franco, Universidad Nacional Autónoma de México, Alberto Carraminana, Instituto Nacional de Astrofisica, Optica y Electronica, Tonantzintla, Mexico
  • Publisher: Cambridge University Press
  • https://doi.org/10.1017/CBO9780511564666.034
  • pp 218-222
Export citation
Summary

The question of the shape of the density PDF for supersonic turbulence is addressed, using both analytical and numerical methods. For isothermal supersonic turbulence, the PDF is Log-Normal, with a width that scales approximately linearly with the Mach number. For a polytropic equation of state, with an effective gamma smaller than one, the PDF becomes skewed and becomes reminiscent of (but not identical to) a power-law on the high density side.

Introduction

The Probability Density Function of mass density is an important statistical property of the ISM that relates, for example, to gravitational collapse and star formation. Log-Normal PDFs have been discussed occasionally in both the cosmological and interstellar contexts (Hubble 1934, Peebles 1980, Ostriker 1984, Zinnecker 1984, Coles & Jones 1991). Vázquez-Semadeni (1994) noticed that the density PDFs in his 2-D numerical simulations of turbulence were consistent with a Log-Normal, and discussed possible reasons for the lognormality. Padoan et al. (1997) showed that the standard deviation of the Log-Normal PDFs in their isothermal 3-D simulations was approximately equal to half the rms Mach number. Scalo et al. (1998) raised the questions of how a polytropic equation of state, and more generally a realistic ISM cooling function, might influence the PDF.

In this contribution we investigate the question of the shape of the PDF for isothermal and polytropic equations of state, using analytical methods and by looking at results from 3-D simulations of supersonic turbulence.

Recommend this book

Email your librarian or administrator to recommend adding this book to your organisation's collection.

Interstellar Turbulence
  • Online ISBN: 9780511564666
  • Book DOI: https://doi.org/10.1017/CBO9780511564666
Please enter your name
Please enter a valid email address
Who would you like to send this to *

CAPTCHA *

Skip to the audio challenge
×
Cancel
Confirm
×