ACP Seminar (Astronomy - Cosmology - Particle Physics)

Speaker: Richard Ellis (Caltech)
Title: Observations of Star Forming Galaxies in the Heart of the Reionization Era
Date (JST): Tue, Jan 28, 2014, 13:30 - 15:00
Place: Balcony A
Related File: 1129.pdf
Abstract: Deep exposures with the Hubble Space Telescope (HST) have provided the primary evidence that star-forming galaxies were present in the first billion years of cosmic history. Sometime during this early period the intergalactic medium transitioned from a neutral gas to one that is fully ionized. How did this `cosmic reionization' occur and were star-forming galaxies responsible? The electron scattering optical depth inferred from cosmic microwave background observations suggests that reioniza tion occurred sometime in the redshift interval z=20 to z=6 so probing the abundance, luminosity distribution and spectral properties of galaxies during this uncharted period holds the key to addressing these fundamental questions. Recent imaging with HST's Wide Field Camera 3 in conjunction with Spitzer photometry and Keck spectroscopy has provided important new insight into understanding when reionization occurred and the role of early galaxies in the process. I will review this progress and discuss the remaining challenges ahead of future facilities such as TMT and JWST.