Theory for SDSS-III

Ohio State University, The, Columbus OH

Investigators

Abstract

SDSS-III, the third phase of the Sloan Digital Sky Survey, will produce unprecedented spectroscopic data sets for studying the matter and energy contents of the universe, cosmological initial conditions, and the physics of galaxy formation. This project covers theoretical research targeted at two of the four SDSS-III surveys: BOSS, the Baryon Oscillation Spectroscopic Survey, which will measure redshifts of one-and-a-half million luminous galaxies and Lyman-alpha forest spectra of a hundred and fifty thousand quasars, and APOGEE, the Apache Point Observatory Galactic Evolution Experiment, which will measure high-resolution near-infrared spectra of a hundred thousand stars from all regions of the Milky Way. The high density of quasar sightlines in BOSS enables a three-dimensional treatment of the Lyman-alpha forest on large scales. Dr. Weinberg and collaborators will use analytic models to investigate the sensitivity of cross-sightline flux statistics to cosmological parameters. They will devise numerical methods to predict these statistics with the accuracy demanded by high-precision data, and they will investigate possible signatures of Helium-II reionization that might be detectable in the 3-D forest or in measurements of close quasar pairs. The team will apply halo occupation distribution (HOD) modeling to BOSS galaxy maps to infer the growth and merger history of luminous galaxies. They will use HOD-based methods to sharpen the cosmological constraints from BOSS. For the APOGEE data, the research team will construct predictive models that combine chemical evolution prescriptions with numerical simulations of disk galaxy formation in a cold dark matter universe, and combine them with APOGEE's revolutionary data set of detailed observations of the Milky Way, to test galaxy formation theory. A variety of simulations, including disks evolved in isolation, disks perturbed by dark matter subhalos and merging satellites, and hydrodynamic simulations, will enable the research group to isolate different physical effects. SDSS-III will have an enormous impact within the astronomical community and beyond, by creating public data archives that enable a broad range of scientific investigations and educational activities. By enhancing his scientific involvement with SDSS-III, this research will support Dr. Weinberg's role as the SDSS-III Project Scientist, working with the science teams of the four surveys to ensure that they produce high-quality data sets. Dr. Weinberg will also continue his multi-year collaboration with Macarthur Award winning artist Josiah McElheny to use cosmologically inspired sculptures as a basis for public outreach aimed at science- and art-oriented audiences.