Merger-remnant galaxies hosting dual supermassive black holes with kpc-scale separations are an expected consequence of galaxy mergers, and these dual supermassive black holes are useful as direct observational tracers of galaxy evolution. I will describe a systematic survey of dual supermassive black holes, which employs a combination of large spectroscopic surveys of galaxies, longslit spectroscopy, and X-ray and radio observations to identify dual supermassive black holes that power active galactic nuclei. I will present the initial results of this search, which will ultimately yield a large observational catalog of dual supermassive black holes. This catalog will enable new measurements of not only the galaxy merger rate, but also of black hole mass growth via gas accretion during mergers and the black hole merger rate of interest for future gravitational wave experiments.
Followed by wine and cheese in Pupin 1402.