title: Black holes.
abstract: Recent progress in black hole research is illustrated by three examples. We discuss the observational challenges that were met to show that a supermassive black hole exists at the center of our galaxy. Stellar-size black holes have been studied in x-ray binaries and microquasars. Finally, numerical simulations have become possible for the merger of black hole binaries.
authors.affiliation: Max Planck Institute for Gravitational Physics, Albert Einstein Institute, Am Mühlenberg 1, 14476 Golm, Germany. bruegman@aei-potsdam.mpg.de
authors.forename: B
authors.initials: B
authors.lastname: Brügmann
authors.forename: A M
authors.initials: AM
authors.lastname: Ghez
authors.forename: J
authors.initials: J
authors.lastname: Greiner