XXIVth IAP Colloquium

Far away : light in the young universe at redshift beyond three

Monday July 7 to Friday July 11, 2008

WHALEN's Presentation

Type of presentation: oral
Title of your presentation : How the First Stars Regulated Local Star Formation: Radiative Feedback

Radiation from the first stars profoundly influenced subsequent star formation in their neighborhood at high redshifts. Their intense UV radiation both evaporated and drove chemistry in cosmological halos clustered in their vicinity. Until recently, the consensus was that the photoevaporation and photodissociation of nearby clouds would essentially quench new star formation. Our recent numerical simulations that self-consistently couple radiation, hydrodynamics, and chemistry suggest otherwise: the radiation is much less destructive to star formation than previously supposed, and may even accelerate it in certain circumstances. We find that satellite halos with central densities above 2000 cm^-3 are essentially immune to local radiative feedback, while those with densities less than 2 - 3 cm^-3 are destroyed anywhere they reside in the cluster. Star formation in halos of intermediate density may either be delayed or enhanced depending on their proximity to the parent star. I will present simple rules for radiative feedback according to halo mass and distance from the parent star derived from the parameter space surveyed by our models.

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