"Stellar Remnants as Cosmological Probes"

White dwarfs represent the eventual end products of 98% of all stars. As such, their luminosity and mass distributions can be used to understand the properties of their progenitor populations (e.g., the initial mass function of stars). In this talk, I will summarize recent results from a large imaging and spectroscopic survey aimed at characterizing samples of white dwarfs in rich star clusters of different ages and metallicities. These data have now provided constraints on the initial-to-final mass relation (i.e., what mass main-sequence star maps to white dwarf mass) over a large mass range (M_initial = 1 -- 7 Msun), and therefore are a powerful
input to chemical evolution models of galaxies including enrichment in the interstellar medium. I will also highlight how these results can be used to measure the age of the Galactic disk and halo. Finally, I will discuss direct empirical evidence that stellar mass loss is much more efficient in high metallicity environments. This result that may be critical in interpreting the UV upturn in elliptical galaxies, the dearth of planets around white dwarfs, and the different rates (and properties) of type Ia SNe in elliptical vs spiral galaxies.