The imprint of pop III stars on the first galaxies.

Here we present three adaptive mesh refinement radiation hydrodynamics simulations that illustrate the impact of momentum transfer from ionising radiation to the absorbing gas on star formation in high-redshift dwarf galaxies. Momentum transfer is calculated by solving the radiative transfer equation with a ray tracing algorithm that is adaptive in spatial and angular coordinates. We find that momentum input partially affects star formation by increasing the turbulent support to a three-dimensional rms velocity equal to the circular velocity of early haloes. Compared to a calculation that neglects radiation pressure, the star formation rate is decreased by a factor of five to 1.8 × 10-2 M⊙ yr-1 in a dwarf galaxy with a dark matter and stellar mass of 2.0 × 108 M⊙ and 4.5 × 105 M⊙, respectively, when radiation pressure is included. Its mean metallicity of 10-2.1 Z⊙ is consistent with the observed dwarf galaxy luminosity-metallicity relation. In addition to photo-heating in H II regions, radiation pressure further drives dense gas from star forming regions, so supernovae feedback occurs in a warmer and more diffuse medium, launching metal-rich outflows. [ABSTRACT FROM AUTHOR]