ABSTRACT:
Wide-field sapectroscopic surveys of the distant universe present an apparent tension between "large N" and "high SNR", with cosmologists and astronomers respectively pulling in opposing directions. I will present a case for the large-N/low-SNR regime not as an unavoidable concession to cosmologists, but as an objective design goal for astronomers, especially for precision mapping of the evolution of massive galaxies across redshift and physical parameter space. Two illustrative examples will be drawn from the Baryon Oscillation Spectroscopic Survey (BOSS) of the SDSS-III. First, I will present our measurements of the evolution of the luminosity function and velocity-dispersion function of massive galaxies using hierarchical statistical modeling. Second, I will describe the discovery and analysis of a large and homogeneous sample of new gravitational lens galaxies at significant cosmological look-back time, which provides evidence of unexpected late-time evolution in the structure and dynamics of massive galaxies.