Dr. Dan Whalen
LANL

University of Florida Astronomy Colloquium - Nov. 28th, 2007

Early Radiative Feedback in Primordial Star Formation

The cosmological halos that hosted the first stars in the universe tended to form in small swarms due to an effect known as cluster bias. How a star in one halo influenced star formation in its neighbors is key to understanding how global star formation rates are regulated at high redshift. I will discuss numerical simulations of the photoevaporation of cosmological halos clustered around a 120 solar mass primordial star, examining only those structures capable of hosting Population III star formation. The calculations include self-consistent multifrequency conservative transfer of UV photons and nine-species primordial chemistry coupled to hydrodynamics. The ultimate fates of these halos fall into one of four categories. Diffuse halos are completely destroyed anywhere they reside in the cluster while denser halos are impervious to both ionizing and Lyman-Werner flux, so collapse of their cores proceeds without delay. Star formation in halos of intermediate central densities can either be accelerated or suppressed, depending on their proximity to the star.