The Universe at $Z>5$: when and how did the `Dark Age' End?

Abstract

This paper considers how the first subgalactic structures produced the UV radiation that ionized the intergalactic medium before $z=5$, and the `feedback' effects of the UV radiation on structure formation. The relevance of pregalactic activity to heavy element production and the origin of magnetic fields is briefly addressed.

6 pages LaTeX, no figures, special style file included