Reionization & First Stars

The reionization epoch marks the period when the first stars formed and produced ultra-violet photons that subsequently ionized most of the Universe's hydrogen. The epoch is arguably the least understood period in the lifetime of the Universe, and it marks the transition from a simple, homogeneous universe to a rich, structure-filled universe. TA scientists are working to understand the properties of the first stars -- which can be much larger and hotter than the stars in the Milky Way --, the large-scale morphology of the reionization epoch, as well as its potential observational signatures.