ABSTRACT:
Empirical scaling relationships between massive galaxies and their central black holes suggest an evolutionary connection between black hole growth and the build-up of spheroidal stellar systems. Upon deeper inspection, however, a variety of scenarios are required to explain the full range of galaxy properties and black hole masses. I will discuss possible assembly scenarios for the most massive elliptical galaxies and present new measurements of black hole masses in nearby Brightest Cluster Galaxies (BCGs). These measurements include two black holes with at least ten billion solar masses, which are the most massive black holes detected by direct dynamical methods and may represent the previously elusive remnants of the most luminous high-redshift quasars. A compilation of new and existing measurements suggests that BCGs have large intrinsic scatter in black hole mass, rather than the tight relationship between stellar luminosity and black hole mass expected from successive hierarchical mergers.