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Turbulence evolution in a density-stratified medium differs from that of homogeneous isotropic turbulence described by the Kolmogorov picture. We evaluate the degree of this effect in the intracluster medium (ICM) with hydrodynamical…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-13 Xun Shi , Congyao Zhang

We propose a new, physically motivated fitting function for density PDFs in turbulent gas. Although it is known that when gas is isothermal, the PDF is approximately lognormal in the core, high-resolution simulations show large deviations…

Astrophysics of Galaxies · Physics 2013-07-02 Philip F. Hopkins

Dealing numerically with the turbulent nature and non-linearity of the physical processes involved in the ISM requires the use of sophisticated numerical schemes coupled to HD and MHD mathematical models. SNe are the main drivers of the…

Astrophysics · Physics 2007-05-23 Miguel A. de Avillez , Dieter Breitschwerdt

We compare velocity structure in the Polaris Flare molecular cloud at scales ranging from 0.015 pc to 20 pc to simulations of supersonic hydrodynamic and MHD turbulence computed with the ZEUS MHD code. We use several different statistical…

Astrophysics · Physics 2007-05-23 Volker Ossenkopf , Mordecai-Mark Mac Low

Recent numerical simulations of the interstellar medium driven by energy input from supernovae and stellar winds indicate that HI clouds can be formed by compression in shock waves and colliding turbulent streams without any help from…

Astrophysics · Physics 2007-05-23 Anvar Shukurov

The warm neutral medium (WNM) was thought to be subsonically/transonically turbulent, and it lacks a network of intertwined filaments that are commonly seen in both molecular clouds and cold neutral medium (CNM). Here, we report HI~21 cm…

We study the formation of giant dense cloud complexes and of stars within them by means of SPH numerical simulations of the mildly supersonic collision of gas streams (``inflows'') in the warm neutral medium (WNM). The resulting…

[abridged] The interstellar medium is now widely recognized to display features ascribable to magnetized turbulence. With the public release of Planck data and the current balloon-borne and ground-based experiments, the growing amount of…

Astrophysics of Galaxies · Physics 2018-06-27 F. Levrier , J. Neveu , E. Falgarone , F. Boulanger , A. Bracco , T. Ghosh , F. Vansyngel

The Interstellar Medium (ISM) is a complex, multi-phase system, where the history of the stars occurs. The processes of birth and death of stars are strongly coupled to the dynamics of the ISM. The observed chaotic and diffusive motions of…

Astrophysics of Galaxies · Physics 2011-02-02 D. Falceta-Goncalves

We determine the physical properties and turbulence driving mode of molecular clouds formed in numerical simulations of a Milky Way-type disc galaxy with parsec-scale resolution. The clouds form through gravitational fragmentation of the…

Astrophysics of Galaxies · Physics 2017-05-31 Keitaro Jin , Diane M. Salim , Christoph Federrath , Elizabeth J. Tasker , Asao Habe , Jouni T. Kainulainen

This study is motivated by recent observations on ubiquitous interstellar density filaments and guided by modern theories of compressible magnetohydrodynamic (MHD) turbulence. The interstellar turbulence shapes the observed density…

Astrophysics of Galaxies · Physics 2019-08-07 Siyao Xu , Suoqing Ji , A. Lazarian

Radio-wave scintillation observations reveal a nearly Kolmogorov spectrum of density fluctuations in the ionized interstellar medium. Although this density spectrum is suggestive of turbulence, no theory relevant to its interpretation…

Astrophysics · Physics 2009-11-06 Yoram Lithwick , Peter Goldreich

Turbulence is ubiquitous in the interstellar medium (ISM) of the Milky Way and other spiral galaxies. The energy source for this turbulence has been much debated with many possible origins proposed. The universality of turbulence, its…

Astrophysics of Galaxies · Physics 2015-06-23 D. Falceta-Goncalves , I. Bonnell , G. Kowal , J. Lepine , C. Braga

Context. Supersonic disordered flows accompany the formation and evolution of MCs. It has been argued that turbulence can support against gravitational collapse and form hierarchical sub-structures. Aims. We study the time evolution of…

Astrophysics of Galaxies · Physics 2019-10-02 Roxana-Adela Chira , Juan~Camilo Ibáñez-Mejía , Mordecai-Mark Mac Low , Thomas Henning

Supernova (SN) feedback is one of the key processes shaping the interstellar medium (ISM) of galaxies. SNe contribute to (and in some cases may dominate) driving turbulence in the ISM and accelerating galactic winds. Modern cosmological…

Astrophysics of Galaxies · Physics 2016-01-11 Davide Martizzi , Claude-Andre Faucher-Giguere , Eliot Quataert

We present the results of three-dimensional simulations of supersonic Euler turbulence with grid resolutions up to 1024^3 points. Our numerical experiments describe nonmagnetized driven turbulent flows with an isothermal equation of state…

Astrophysics · Physics 2008-11-26 Alexei G. Kritsuk , Rick Wagner , Michael L. Norman , Paolo Padoan

The universality of interstellar turbulence is examined from observed structure functions of 27 giant molecular clouds and Monte Carlo modeling. We show that the structure functions, dv=v0 l^gamma, derived from wide field imaging of CO…

Astrophysics · Physics 2009-11-10 Mark Heyer , Christopher Brunt

The hot intracluster medium (ICM) is thought to be quiescent with low observed velocity dispersions. Surface brightness fluctuations of the ICM also suggest that its turbulence is subsonic with a Kolmogorov scaling relation, indicating that…

Under ideal MHD conditions the magnetic field strength should be correlated with density in the interstellar medium (ISM). However, observations indicate that this correlation is weak. Ambipolar diffusion can decrease the flux-to-mass ratio…

Astrophysics · Physics 2009-11-10 F. Heitsch , E. G. Zweibel , A. D. Slyz , J. E. G. Devriendt

Molecular clouds are to a great extent influenced by turbulent motions in the gas. Numerical and observational studies indicate that the star formation rate and efficiency crucially depend on the mixture of solenoidal and compressive modes…

Astrophysics of Galaxies · Physics 2017-10-11 Bastian Körtgen , Christoph Federrath , Robi Banerjee
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