Physics & Astronomy, University of Utah
Thursday, Oct 6, 2011
Refreshments: 3:30 pm in 219 JFB
Lecture 4:00pm (102 JFB)
Title: Quantity is Quality: Studying Galaxy Evolution with Cosmological Redshift Surveys
Over the past 10 years, the study of galaxies in the present-day universe has been revolutionized by the statistical power of the million-galaxy Sloan Digital Sky Survey (SDSS). The next-generation SDSS-III is now obtaining spectra of an even larger number of galaxies at an earlier cosmic epoch. The combination of these two surveys presents a unique opportunity for the study of galaxy evolution. However, the greater distances of SDSS-III target galaxies make them significantly fainter than those of the original SDSS, necessitating work in an extremely low-signal, high-background regime. I will describe my ongoing work as a "software spectroscopist" to develop and implement new analysis methods to address this challenge, in order to realize the full scientific potential of these and other ambitious surveys. Within this context, I will present the results of a hierarchical Bayesian analysis method to accurately measure the population distribution of physical galaxy parameters from large numbers of low signal-to-noise spectra, even when the parameters of interest cannot be measured on a galaxy-by-galaxy basis. I will also present the results of a Hubble Space Telescope imaging survey for strong gravitational lenses discovered like needles in a haystack from within the SDSS-III spectroscopic database. Finally, I will describe how the same advanced spectroscopic algorithms that are needed to enable the study of faint galaxies in the distant universe may hold the key to the discovery of Earth-mass extrasolar planets.