ANISOTROPIC FORMATION of MAGNETIZED CORES in TURBULENT CLOUDS

Che Yu Chen, Eve Charis Ostriker

Research output: Contribution to journalArticle

26 Scopus citations

Abstract

In giant molecular clouds (GMCs), shocks driven by converging turbulent flows create high-density, strongly magnetized regions that are locally sheetlike. In previous work, we showed that within these layers, dense filaments and embedded self-gravitating cores form by gathering material along the magnetic field lines. Here, we extend the parameter space of our three-dimensional, turbulent MHD core formation simulations. We confirm the anisotropic core formation model we previously proposed and quantify the dependence of median core properties on the pre-shock inflow velocity and upstream magnetic field strength. Our results suggest that bound core properties are set by the total dynamic pressure (dominated by large-scale turbulence) and thermal sound speed cs in GMCs, independent of magnetic field strength. For models with a Mach number between 5 and 20, the median core masses and radii are comparable to the critical Bonnor-Ebert mass and radius defined using the dynamic pressure for Pext. Our results correspond to and for and v0, the large-scale mean density and velocity. For our parameter range, the median, but a very high pressure cloud could have lower characteristic core mass. We find cores and filaments form simultaneously, and filament column densities are a factor of ∼2 greater than the surrounding cloud when cores first collapse. We also show that cores identified in our simulations have physical properties comparable to those observed in the Perseus cloud. Superthermal cores in our models are generally also magnetically supercritical, suggesting that the same may be true in observed clouds.

Original languageEnglish (US)
Article number126
JournalAstrophysical Journal
Volume810
Issue number2
DOIs
StatePublished - Sep 10 2015

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • ISM: magnetic fields
  • magnetohydrodynamics (MHD)
  • stars: formation
  • turbulence

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