# Gravitation and Black Hole Theory

Black holes are among the most fascinating objects in the Universe. These magnificently dense spherical conglomerates of rotating matter, exhibiting strong gravitational effects, are thought to be entailed with event horizons – special regions of space-time from which not even light can escape. Data from a vast number of astrophysical experiments will provide solid evidence (images) of event horizons and hence confirmation that black holes exist. Once thought to be mere static pockets of matter, we now know that black holes lurk at the center of every Galaxy, including the Milky Way, and spin producing the most bewildering effects such as matter accretion and large scale jets. Fully elucidating the mechanisms driving these effects is one of the aims of the group.

Four-dimensional General Relativity leaves room only for spherical event horizon black holes. In more than four space-time dimensions, however, new striking possibilities open up. Besides the spherical configurations, there are non-spherical event horizon topologies and multi-black hole solutions. Higher-dimensional black holes thus have a much richer and still not fully understood phase structure than their four-dimensional counterparts. Recently, in an ambitious effort to elucidate the entire population of black hole configurations many explicit solutions have been unveiled. In spite of the remarkable progress, key explicit examples of conjectured black holes are still missing. Finding these elusive black hole solutions of Einstein’s Theory, is one of the other research lines of the group.