Galaxy Evolution during the Epoch of Reionization
Steve Finkelstein, University of Texas at Austin
Abstract: The advent of the Wide Field Camera 3 on the Hubble Space Telescope has heralded a new era in our ability to study the earliest phases of galaxy formation and evolution. The number of candidates for galaxies now known at redshifts greater than six has grown to be in the thousands. This allows us to move beyond mere counting of galaxies, to endeavor to understand the detailed physics regulating the growth of galaxies. I will review the recent progress our group in Texas has made in this arena using the exquisite datasets from the CANDELS and Frontier Fields programs. Specifically, our detailed new measurements of both the evolution of the stellar mass function and rest-frame UV luminosity function now allow us to probe the effect of feedback on low-mass galaxies, the star-formation efficiency in high-mass galaxies, and the contribution of galaxies to the reionization of the universe. Our most recent result comes from the Frontier Fields, where we have used an advanced technique to remove the light from the cluster galaxies to uncover z > 6 galaxies as faint as M_UV=-13. Our updated luminosity functions show no sign of a turnover down to these extremely faint levels, providing the first empirical test of reionization models which require such faint galaxies, and is in modest tension with simulations which predict a turnover at brighter levels. I will also discuss our spectroscopic followup efforts, which have yielded two of the four highest redshift confirmed galaxies, and also provide further insight into reionization, by the scattering of Lyman alpha emission by neutral gas in the intergalactic medium. I will conclude with a look ahead to the problems we can expect to tackle with ALMA, JWST, and even more future facilities.
Preparing to Explore the Universe with the James Webb Space Telescope
Dr. Jane Rigby (NASA Goddard, Deputy Project Scientist for JWST)
Abstract: NASA’s James Webb Space Telescope (JWST), scheduled to be launched in 2019, will revolutionize our view of the Universe. As the scientific successor to the Hubble Space Telescope, JWST will rewrite the textbooks and return gorgeous images and spectra of our universe. In my talk, I will show how JWST will revolutionize our understanding of how galaxies and supermassive black holes formed in the first billion years after the Big Bang, and how they evolved over cosmic time. I’ll describe how our international team is preparing for launch, how we decide what targets to observe, and how we are testing the telescope to be sure it will work in space.
More information about the telescope can be found at https://www.jwst.nasa.gov/.