期刊
ASTROPHYSICAL JOURNAL
卷 714, 期 1, 页码 287-295出版社
IOP PUBLISHING LTD
DOI: 10.1088/0004-637X/714/1/287
关键词
cosmology: theory; galaxies: evolution; galaxies: formation; methods: numerical; stars: formation
资金
- DOE
- NSF [AST-0507596, AST-0708154]
- Kavli Institute for Cosmological Physics at the University of Chicago through the NSF [PHY-0551142]
- Kavli Foundation
- Fermilab
- Kavli Institute for Cosmological Physics
- University of Chicago
We present results of self-consistent, high-resolution cosmological simulations of galaxy formation at z similar to 3. The simulations employ a recently developed recipe for star formation based on the local abundance of molecular hydrogen, which is tracked self-consistently during the course of simulation. The phenomenological H(2) formation model accounts for the effects of dissociating UV radiation of stars in each galaxy, as well as self-shielding and shielding of H(2) by dust, and therefore allows us to explore effects of lower metallicities and higher UV fluxes prevalent in high-redshift galaxies on their star formation. We compare stellar masses, metallicities, and star formation rates of the simulated galaxies to available observations of the Lyman break galaxies (LBGs) and find a reasonable agreement. We find that the Kennicutt-Schmidt (KS) relation exhibited by our simulated galaxies at z approximate to 3 is substantially steeper and has a lower amplitude than the z = 0 relation at Sigma(H) less than or similar to 100 M(circle dot) pc(-2). The predicted relation, however, is consistent with existing observational constraints for the z approximate to 3 damped Ly alpha and LBGs. Our tests show that the main reason for the difference from the local KS relation is lower metallicity of the interstellar medium in high-redshift galaxies. We discuss several implications of the metallicity-dependence of the KS relation for galaxy evolution and interpretation of observations. In particular, we show that the observed size of high-redshift exponential disks depends sensitively on their KS relation. Our results also suggest that significantly reduced star formation efficiency at low gas surface densities can lead to strong suppression of star formation in low-mass high-redshift galaxies and long gas consumption time scales over most of the disks in large galaxies. The longer gas consumption time scales could make disks more resilient to major and minor mergers and could help explain the prevalence of the thin stellar disks in the local universe.
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