Ryan M. O'Leary, Abraham Loeb
During the formation of the Milky Way, > 100 central black holes (BHs) may
have been ejected from their small host galaxies as a result of asymmetric
gravitational wave emission. We previously showed that many of these BHs are
surrounded by a compact cluster of stars that remained bound to the BH during
the ejection process. In this paper, we perform long term N-body simulations of
these star clusters to determine the distribution of stars in these clusters
today. These numerical simulations, reconciled with our Fokker-Planck
simulations, show that stellar density profile follows a power-law with slope ~
-2.15, and show that large angle scattering and tidal disruptions remove 20 -
90% of the stars by ~10^10 yr. We then analyze the photometric and
spectroscopic properties of recoiled clusters accounting for the small number
of stars in the clusters. We use our results to perform a systematic search for
candidates in the Sloan Digital Sky Survey. We find no spectroscopic
candidates, in agreement with our expectations from the completeness of the
survey. Using generic photometric models of present day clusters we identify
~100 recoiling cluster candidates. Follow-up spectroscopy would be able to
determine the nature of these candidates.
View original:
http://arxiv.org/abs/1102.3695
No comments:
Post a Comment