The properties and distribution of void galaxies provide critical tests of galaxy formation models, complementary to observations of galaxies in denser regions. Preliminary analyses indicate significant environmental dependences for star formation rate, luminosity, color, and morphology, possibly in conflict with the predictions of currently preferred (cold dark matter) models. A new sample, identified from the Sloan Digital Sky Survey and augmented with other archival data and proposed observations, will allow a detailed investigation of variations in galaxy properties, and of specific explanatory hypotheses. Statistical measures of voids will strongly constrain dark matter models. Clustering within voids will be studied for evidence of substructure. Special purpose simulations will be developed to probe the structure and dynamics of voids, and to help interpret the data.
Broader impacts include community outreach, with a physics open house and demonstrations for high school students. University efforts will include new undergraduate and graduate courses, student mentoring, and the organization of local and international meetings.
