Title: Self-similar growth of black holes in the Friedmann universe
Speaker: Hideki Maeda (Valdivia Chile)
Abstract: It is quite presumable from recent observations that there exists a huge black hole with millions of solar mass at the center of most galaxies. There are many scenarios proposed for the formation of such supermassive black holes. Among them, the scenario proposed by Zeldovich and Novikov in 1967 is a very attractive one, in which a tiny black holes formed in the very early universe grows very rapidly in a self-similar manner and becomes a giant black hole. Realistic black holes, especially those in the early universe when the expansion effects are far from negligible, should be modeled by black hole solutions that include matter fields in an expanding universe. In order to clarify the possibility of the scenario by Zeldovich and Novikov, we study the self-similar spherically symmetric solutions which are asymptotic to the Friedmann universe at spatial infinity. The (non)- existence of the solutions and the properties of the self-similar black holes in the presence of a scalar field or a perfect fluid are discussed.