Institute for Advanced Study Astrophysics Seminar

I will present a novel model of star formation based on non-equilibrium treatment of molecular hydrogen in self-consistent cosmological simulations of galaxy formation, including effects of self-shielding and shielding by dust. The model predicts strong dependence of the global Kennicutt-Schmidt star formation relation on the metallicity of the interstellar medium of galaxies (and a weaker dependence on the interstellar UV field) and can explain recent results indicating inefficient star formation in high-redshift Damped Lyman alpha galaxies at z~3. General considerations and some preliminary simulation results indicate that low efficiency of star formation at high redshifts can have significant implications for galaxy formation and may help resolve many of the main problems and puzzles of galaxy formation within hierarchical CDM scenario.