Ostriker and his students have helped develop numerical cosmology. Bode and Ostriker have developed the TPM Code -- Tree-Particle-Mesh Code for Cosmological Simulations and are now performing very large scale dark matter numerical simulations that provide a basis for understanding the rapidly improving X-ray cluster data and in establishing a calibration that will allow an accurate interpretation of the forthcoming SZ surveys. Renyue Cen and Jeremiah Ostriker have developed hydrodynamical simulation codes that have helped shape our understanding of the Lyman alpha forest and the Warm Hot Intergalactic Medium. See a movie of galaxy formation here. Another research focus is to understand effects on the Lyman alpha flux power spectrum determination due to astrophysical processes on small scales in light of the BOSS project of the SDSS III survey. Cen, Mesinger, Wise, and Zaldarriaga have been studying the first stars, cosmological reionization, high-redshift Lyman alpha emitters, and high-redshift 21-cm tomography during reionization, in light of many ongoing/upcoming major observational projects, including the LOFAR, MWA, JWST, PLANCK and LAE surveys.
Princeton students and faculty are playing a leading role in observational cosmology with its faculty leading WMAP (Wilkinson Microwave Anisotropy Probe) and SDSS (Sloan Digital Sky Survey). Currently, David Spergel and his research group are involved in the analysis and interpretation of data from the ACT (Atacama Cosmology Telescope) and are working on follow-up optical observations as part of the Southern Cosmology Survey. Joe Fowler, Lyman Page and Suzanne Staggs (physics) are leading the experimental effort. Michael Strauss, Jim Gunn, and Robert Lupton are helping to define two new upcoming major surveys: a large area survey with HSC (Hyper SuPrime Cam) on Subaru and an all-sky survey with the Large Synoptic Survey Telescope. Gunn continues his leadership role in the Sloan Digital Sky Survey with the new SDSS III survey.