Very massive stars in high-redshift galaxies

Abstract

A significant fraction of Lyα-emitting galaxies (LAEs) at z ≥ 5.7 have rest-frame equivalent widths (EWs) greater than ∼100 Å. However, only a small fraction of the Lyα flux produced by a galaxy is transmitted through the intergalactic medium, which implies intrinsic Lyα EWs that are in excess of the maximum allowed for a Population II stellar population having a Salpeter mass function. In this paper, we study characteristics of the sources powering Lyα emission in high-redshift galaxies. We propose a simple model for Lyα emitters in which galaxies undergo a burst of very massive star formation that results in a large intrinsic EW, followed by a phase of Population II star formation with a l..