Summary
Anthony Pahl is awarded an NSF Astronomy and Astrophysics Fellowship to carry out a program of research and education at Carnegie Science Observatories. The space between galaxies is not completely empty. Rather, it is filled with very low-density atoms, mostly Hydrogen and Helium. In the early phases of the Universe, this intergalactic medium (IGM) is thought to be opaque and neutral, until ionized by the UV light from the first stars. Pahl will develop computer models to study this phase. They will help to determine the precise timing of this phase of cosmic history. The project will also e
