Ionizing Radiation from z = 4-10 Galaxies

TY - JOUR

T1 - Ionizing Radiation from z = 4-10 Galaxies

AU - Razoumov, A. O.

AU - Sommer-Larsen, Jesper

PY - 2010/2/20

Y1 - 2010/2/20

N2 - We compute the escape of ionizing radiation from galaxies in the redshift interval z = 4-10, i.e., during and after the epoch of reionization, using a high-resolution set of galaxies, formed in fully cosmological simulations. The simulations invoke early, energetic feedback, and the galaxies evolve into a realistic population at z = 0. Our galaxies cover nearly four orders of magnitude in masses (107.8-1011.5 M ⊙) and more than five orders in star formation rates (10-3.5-10 1.7 M ⊙ yr-1), and we include an approximate treatment of dust absorption. We show that the source-averaged Lyman limit escape fraction at z = 10.4 is close to 80% declining monotonically with time as more massive objects build up at lower redshifts. Although the amount of dust absorption is uncertain to 1-1.5 dex, it is tightly correlated with metallicity; we find that dust is unlikely to significantly impact the observed UV output. These results support reionization by stellar radiation from low-luminosity dwarf galaxies and are also compatible with Lyman continuum observations and theoretical predictions at z∼3-4.

AB - We compute the escape of ionizing radiation from galaxies in the redshift interval z = 4-10, i.e., during and after the epoch of reionization, using a high-resolution set of galaxies, formed in fully cosmological simulations. The simulations invoke early, energetic feedback, and the galaxies evolve into a realistic population at z = 0. Our galaxies cover nearly four orders of magnitude in masses (107.8-1011.5 M ⊙) and more than five orders in star formation rates (10-3.5-10 1.7 M ⊙ yr-1), and we include an approximate treatment of dust absorption. We show that the source-averaged Lyman limit escape fraction at z = 10.4 is close to 80% declining monotonically with time as more massive objects build up at lower redshifts. Although the amount of dust absorption is uncertain to 1-1.5 dex, it is tightly correlated with metallicity; we find that dust is unlikely to significantly impact the observed UV output. These results support reionization by stellar radiation from low-luminosity dwarf galaxies and are also compatible with Lyman continuum observations and theoretical predictions at z∼3-4.

U2 - 10.1088/0004-637X/710/2/1239

DO - 10.1088/0004-637X/710/2/1239

M3 - Journal article

SN - 0004-637X

VL - 710

SP - 1239

EP - 1246

JO - Astrophysical Journal

JF - Astrophysical Journal

IS - 2

ER -