Informal Astro Talk
Illuminating the Cosmic Dawn
The birth of the first stars, black holes and galaxies heralded the end of the cosmic Dark Ages and the beginning of the Cosmic Dawn. The light from these objects heated and ionized almost every atom in existence, culminating in the Epoch of Reionization: the final major phase change of the Universe. This final frontier of astrophysical cosmology is undergoing a transition from an observationally-starved epoch to a "Big Data" field. This process will culminate with interferometric observations of the redshifted 21-cm line, eventually providing a 3D map of the first billion years of our Universe. I will discuss the recent clues to reionization, obtained from the CMB, high-redshift galaxies, and quasars. I will present the first detection (2 sigma) of ongoing reionization, found in the spectrum of a z=7.1 quasar. Finally, I will showcase the physical bounty of the upcoming 21-cm observations. I will discuss the innovative modeling techniques we are developing to tap into this bounty, allowing us to constrain astrophysical parameters in a fully Bayesian framework.