Cosmology: Cool start to hydrogen ionization

Cosmology: Cool start to hydrogen ionization

Nature 506, 7487 (2014). doi:10.1038/nature13051

Authors: Judd D. Bowman

Simulations of the cosmos cast doubt on assumptions about the temperature of primordial hydrogen gas when it was ionized by the first stars and galaxies, complicating the interpretation of ongoing observations. See Letter p.197