Control of star formation in galaxies by gravitational instability

Yuexing Li, Mordecai Mark Mac Low, Ralf S. Klessen

Research output: Contribution to journalArticlepeer-review

69 Scopus citations


We study gravitational instability and consequent star formation in a wide range of isolated disk galaxies, using three-dimensional smoothed particle hydrodynamics simulations at a resolution sufficient to fully resolve gravitational collapse. Stellar feedback is represented by an isothermal equation of state. Absorbing sink particles are inserted in dynamically bound, converging regions with number density n > 103 cm-3 to directly measure the mass of gravitationally collapsing gas available for star formation. Our models quantitatively reproduce not only the observed Schmidt law, but also the observed star formation threshold in disk galaxies. Our results suggest that the dominant physical mechanism determining the star formation rate is just the strength of gravitational instability, with feedback primarily functioning to maintain a roughly constant effective sound speed.

Original languageEnglish (US)
Pages (from-to)L19-L22
JournalAstrophysical Journal
Issue number1 II
StatePublished - Feb 10 2005

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


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