标题： 来自星系形成的反馈：高红移星系逃逸的电离辐射 显示英文标题

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

摘要： 多个观测和理论论证表明，于红移 z > 3 的星暴星系可能与类星体一样成为宇宙再电离辐射的重要来源。z > 5 时星系际介质（IGM）的再电离可能部分由第一代明亮的大质量恒星引发。为了成为来自恒星形成的重要辐射反馈源，必须有相当大比例（\sim 1-10%）的电离光子逃逸出星系的气体层。我们利用暗物质（DM）势场所限制的平滑分布气体模型，估算球状星系晕逃逸的Lyc通量比例 f_esc，该比例随星系质量和非定常化红移变化。通过求解暗物质晕势阱中重子物质的流体力学平衡方程来找到气体密度分布，Navarro等人（1996年）给出了暗物质晕的密度分布。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）、恒星密度分布以及OB联星群亮度函数的依赖性。我们给出了 f_esc(z,M_{DM}) 的有用解析公式。使用 Press-Schechter 形式主义，我们发现 z \sim 7 时的恒星再电离可能主要由小的星系次单元主导，其质量为 M_{DM} \simlt 10^7 M_\odot 且恒星形成效率为银河系的 SFE \sim 10 倍。这可能影响重元素在整个星系际介质中的分布。 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 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, 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.