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Author Fall, S. Michael ♦ Krumholz, Mark R. ♦ Matzner, Christopher D.
Source arXiv.org
Content type Text
File Format PDF
Date of Submission 2009-10-12
Language English
Subject Domain (in DDC) Computer science, information & general works ♦ Natural sciences & mathematics ♦ Astronomy & allied sciences ♦ Physics
Subject Keyword Astrophysics - Solar and Stellar Astrophysics ♦ Astrophysics - Astrophysics of Galaxies ♦ physics:astro-ph
Abstract We investigate how the removal of interstellar material by stellar feedback limits the efficiency of star formation in molecular clouds and how this determines the shape of the mass function of young star clusters. In particular, we derive relations between the power-law exponents of the mass functions of the clouds and clusters in the limiting regimes in which the feedback is energy-driven and momentum-driven, corresponding to minimum and maximum radiative losses and likely to bracket all realistic cases. We find good agreement between the predicted and observed exponents, especially for momentum-driven feedback, provided the protoclusters have roughly constant mean surface density, as indicated by observations of the star-forming clumps within molecular clouds. We also consider a variety of specific feedback mechanisms, concluding that HII regions inflated by radiation pressure predominate in massive protoclusters, a momentum-limited process when photons can escape after only a few interactions with dust grains. We then present a first estimate of the star formation efficiency in this case, finding that it depends on the masses and sizes of the protoclusters only through their mean surface density, thus ensuring consistency between the observed power-law exponents of the mass functions of the clouds and clusters. The numerical value of this efficiency is also consistent with observations.
Description Comment: 5 pages, 3 figures, emulateapj format, version accepted to ApJL
Educational Use Research
Learning Resource Type Article
Page Count 5


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