Friday, November 30, 2012
Zooming in on Galactic Nuclei at the Dawn of Gravitational Wave Astronomy
Bence Kocsis, Einstein Fellow, Center for Astrophysics, Harvard University
The rapid development of gravitational wave instruments will open a completely new
window on the Universe. In this talk, I will describe how this may revolutionize our
understanding of galactic nuclei. Galactic nuclei host a central supermassive black hole,
a dense population of stars and compact objects, and in many cases a bright gaseous
disk feeding the central supermassive black hole. These systems may be a treasure trove
of gravitational wave sources. Recent electromagnetic observations revealed interesting
structures including counterrotating disks and an isotropic central cluster of young stars.
I will demonstrate that these structures can be naturally explained by methods commonly
used in condensed matter physics. Stars and compact objects collectively resemble a gigantic
liquid crystal, which can exhibit phase transitions. Gravitational wave observations may tell us
if there is a central dark cluster or dark disk of compact objects. Ground-based gravitational
wave observatories will be able to constrain the distribution and mass function of black holes.
Pulsar timing can provide a detailed map of this region with unprecedented resolution and locate
intermediate mass black holes, if present.