标题： 星系形成反馈：高红移星系电离辐射的逃逸 显示英文标题

标题： Feedback from Galaxy Formation: Escaping Ionizing Radiation from Galaxies at High Redshift

摘要： 一些观测和理论论点表明，在红移z > 3时，星暴星系可能与类星体一样成为宇宙大尺度电离辐射的来源。 在红移z > 5时，星际介质（IGM）的再电离可能部分来源于第一批明亮的大质量恒星。 为了成为恒星形成中重要的辐射反馈来源，必须有大量（\sim 10%）的电离光子逃逸出星系的气体层。 使用由暗物质（DM）势约束的平滑分布气体模型，我们估计了逃逸出球形星系晕的LyC通量比例f_esc，该比例是其质量和动力学红移的函数。 通过求解在暗物质晕势阱中重子物质的流体静力学平衡方程，得到了气体密度分布，该分布由Navarro等（1996）找到的密度分布确定。 然后我们进行参数研究，以理解fesc对红移、质量、恒星形成效率（SFE）、恒星密度分布和OB星团光度函数的依赖性。 我们给出了f_esc(z,M_{DM})的有用解析公式。 利用Press-Schechter形式，我们发现红移z\sim 7时的恒星再电离很可能由小的星系子单元主导，其质量M_{DM} \simlt 10^7 M_\odot ，SFE\sim 10倍于银河系中的值。 这可能会影响重元素在整个星际介质中的分布。 显示英文摘要

摘要： 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 (\sim 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, f_esc, of Lyc 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. (1996). We then perform a parametric study to understand the dependence of fesc on redshift, mass, star-formation efficiency (SFE), stellar density distribution, and OB association luminosity function. We give useful analytical formulas for f_esc(z,M_{DM}). Using the Press-Schechter formalism, we find that stellar reionization at z \sim 7 is probably dominated by small galactic sub-units, with M_{DM} \simlt 10^7 M_\odot and SFE \sim 10 times that in the Milky Way. This may affect the distribution of heavy elements throughout the intergalactic medium.