------------------------------------------------------------------------
From: Simon Portegies Zwart  spz@science.uva.nl 
To: gcnews@aoc.nrao.edu
Subject: submit IMBHinGC.tex ApJ, in press

%astro-ph/0511397

\documentstyle{article}

\title{
The ecology of star clusters and intermediate mass
black holes in the Galactic bulge
}

\author{Simon F.\ Portegies Zwart,
 Holger Baumgardt,
 Stephen L.\ W.\ McMillan,
 Junichiro Makino,
 Piet Hut,
\and Toshi Ebisuzaki
}



\begin{document}
We simulate the inner 100pc of the Milky-Way Galaxy to study the
formation and evolution of the population of star clusters and
intermediate mass black holes. For this study we perform extensive
direct N-body simulations of the star clusters which reside in the
bulge, and of the inner few tenth of parsecs of the super massive
black hole in the Galactic center. In our N-body simulations the
dynamical friction of the star cluster in the tidal field of the bulge
are taken into account via (semi)analytic soluations. The N-body
calculations are used to calibrate a (semi)analytic model of the
formation and evolution of the bulge. We find that about 10\% of the
clusters born within 100pc of the Galactic center undergo core
collapse during their inward migration and form intermediate-mass
black holes (IMBHs) via runaway stellar merging. After the clusters
dissolve, these IMBHs continue their inward drift, carrying a few of
the most massive stars with them. We predict that region within about
10 parsec of the SMBH is populated by about 50IMBHs of some
1000Msun. Several of these are expected to be accompanied still by
some of the most massive stars from the star cluster. We also find
that within a few milliparsec of the SMBH there is a steady population
of several IMBHs. This population drives the merger rate between IMBHs
and the SMBH at a rate of about one per 10Myr, sufficient to build the
accumulate majority of mass of the SMBH. Mergers of IMBHs with SMBHs
throughout the universe are detectable by LISA, at a rate of about two
per week.
\end{document}