Abstract
Several observational and theoretical arguments suggest that starburst galaxies may rival quasars as sources of metagalactic ionizing radiation at redshifts z > 3. Reionization of the intergalactic medium (IGM) at z > 5 may arise, in part, from the first luminous massive stars. To be an important source of radiative feedback from star formation, a substantial fraction (~1%-10%) of the ionizing photons must escape the gas layers of the galaxies. Using models of smoothly distributed gas confined by dark matter (DM) potentials, we estimate the fraction, ⟨fesc⟩ , of Lyman-continuum flux that escapes the halos of spherical galaxies as a function of their mass and virialization redshift. The gas density profile is found by solving the equation of hydrostatic equilibrium for the baryonic matter in the potential well of a DM halo with the density profile found by Navarro et al. We then perform a parametric study to understand the dependence of ⟨fesc⟩ on redshift, mass, baryonic fraction, star formation efficiency (SFE), stellar density distribution, and OB association luminosity function. We give useful analytical formulas for ⟨fesc(z,MDM)⟩. Using the Press-Schechter formalism, we find that stellar reionization at z ~ 7 is probably dominated by small galactic subunits, with MDM ≲ 107 M☉ and SFE ~ 10 times that in the Milky Way. This may affect the distribution of heavy elements throughout the intergalactic medium.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
