The spectrum of a quasar at redshift 7.04 reveals absorption from a large column of foreground neutral hydrogen with no corresponding heavy elements; this absorbing gas is either diffuse and intergalactic but has not yet been ionized by starlight at this early epoch, or it is gravitationally bound to a proto-galaxy that has a chemical abundance <1/10,000 the solar level.
- Robert A. Simcoe
- Peter W. Sullivan
- Adam J. Burgasser
