9401519 Tonry This project will complete a large survey of galaxy distances measured using Surface Brightness Fluctuations (SBF), delineate the velocity field of galaxies within a distance of roughly 3000 km/s, and publish a catalog of these distances and a digital atlas of the galaxy images acquired for this project. The observations are essentially complete for this project, but reductions of data are expected to extend for one year. Once the data set is complete, three topics will be studied during the balance of the proposal period. (1) The Hubble constant will be measured. (2) The peculiar velocity field within 3000 km/s will be mapped more accurately and less subject to environmental effects than in previous studies. (3) The map of peculiar velocities will be used to estimate the mass distribution within and near this volume of space, with emphasis on determining the mass and extent of nearby superclusters and voids without assumptions of a relation between galaxy density and mass density.
