October 28, 1999 CfA Colloquium


Title: Reionization and the Early Intergalactic Medium

Speaker: Piero Madau

Abstract: ABSTRACT: The development of structure in the universe was well advanced at high redshifts. Quasars have been detected to z=5, and the most distant galaxies to even greater distances. The Ly-alpha forest in the spectra of high redshift QSOs shows that the intergalactic medium (IGM) itself developed extensive nonlinear structures by early times. Still unknown, however, is the epoch during which the first generation of stars was formed, and the time scale over which the transition from a neutral universe to one that is almost completely reionized took place. Radiation sources prior to the epoch of reionization may be detected indirectly through their impact on the surrounding neutral IGM and the resulting emission or absorption against the cosmic microwave background.

Student Lunch: Friday 10/29 at 12:00 in A-101

Further Reading: Madau, Haardt, Rees 1999, ApJ, 514, 648