Just after the Big Bang, the universe was filled with a fog of cool hydrogen gas. When the first stars and galaxies began to form, energetic light from these objects heated and ionized this gas, removing the electrons from the hydrogen atoms in a process known as “reionization.” Although we can measure very well when this lifting of the “cosmic haze” was completed (about one billion years after the Big Bang), we still do not know when it started, and what types of objects were responsible for creating the needed energetic photons. In this talk, Dr. Finkelstein will describe past and future efforts with the Keck Observatory telescopes to study this “epoch of reionization,” and discuss exciting new observational programs upcoming with the soon-to-be-launched James Webb Space Telescope to push our observational limit ever closer to the Big Bang to probe the galaxies responsible.W. M. Keck Observatory wishes to offer our deepest gratitude to our Astronomy Talk Series sponsors, Rob and Terry Ryan.
Guest Speaker
Steven Finkelstein
Associate Professor of Astronomy, Provost’s Teaching Fellow
University of Texas at Austin
