Paper: astro-ph/0512344
Date: Tue, 13 Dec 2005 21:05:40 GMT (212kb)

Title: Hypervelocity intracluster stars ejected by supermassive black hole
binaries

Authors: Kelly Holley-Bockelmann, Steinn Sigurdsson, J. Christopher Mihos, John
J. Feldmeier, Robin Ciardullo, and Cameron McBride

Comments: 4 pages, 3 color figures. Submitted to ApJ Letters
\\
Hypervelocity stars have been recently discovered in the outskirts of
galaxies, such as the unbound star in the Milky Way halo, or the three
anomalously fast intracluster planetary nebulae (ICPNe) in the Virgo Cluster.
These may have been ejected by close 3-body interactions with a binary
supermassive black hole (SMBBH), where a star which passes within the semimajor
axis of the SMBBH can receive enough energy to eject it from the system. Stars
ejected by SMBBHs may form a significant sub-population with very different
kinematics and mean metallicity than the bulk of the intracluster stars. The
number, kinematics, and orientation of the ejected stars may constrain the mass
ratio, semimajor axis, and even the orbital plane of the SMBBH. We investigate
the evolution of the ejected debris from a SMBBH within a clumpy and
time-dependent cluster potential using a high resolution, self-consistent
cosmological N-body simulation of a galaxy cluster. We show that the predicted
number and kinematic signature of the fast Virgo ICPNe is consistent with
3-body scattering by a SMBBH with a mass ratio $10:1$ at the center of M87.

\\ ( http://arXiv.org/abs/astro-ph/0512344 , 212kb)