Session D3 - The Discovery of Black Holes.
INVITED session, Saturday afternoon, May 01
Plaza E, Adam's Mark Hotel
Black holes, though exotic and mathematically beautiful, are notoriously difficult to detect because they emit no light of their own and hence can be seen only by their influence on nearby stars and gas. It is therefore probable that the observed stellar-mass and supermassive black holes are only the tip of the iceberg. In addition to the expected undetectable population of solitary black holes, there may be new classes of black holes yet to be discovered. For example, there is growing evidence for an intermediate-mass category of black holes that are too massive to form from solitary stars in the current universe, yet are less massive than the black holes in the centers of galaxies and are not located in environments where growth from gas accretion is significant. An even more intriguing prospect is that in the very early universe a population of primordial black holes could have formed. Although there are currently only limits to such a population, if they formed prior to big bang nucleosynthesis then there is a slim but nonzero chance that primordial black holes are the primary components of dark matter, which would imply that black holes are the dominant form of matter in the universe. We will discuss these scenarios in the context of structure formation and stellar dynamics, and consider future electromagnetic and gravitational wave observations that could yield further insight.