S. L. W. McMillan (Drexel University), S. F. Portegies Zwart (University of Amsterdam)
Close encounters and physical collisions between stars in young dense clusters may lead to the formation of very massive stars and black holes via runaway merging. We examine critically some details of this process, using N-body simulations and simple analytical estimates to place limits on the cluster parameters for which it expected to occur. For small clusters, the mass of the runaway is effectively limited by the total number of high-mass stars in the system. For more massive clusters, the runaway mass is determined by the fraction of stars that can segregate to the cluster core while still on the main sequence. Numerical simulations predict runaway masses in the range commonly cited for intermediate-mass black holes, and raise the intriguing possibility of a significant population of massive black holes in the innermost ~100 pc of the Galaxy. We discuss some observational constraints on these theoretical scenarios.
The author(s) of this abstract have provided an email address for comments about the abstract: steve@physics.drexel.edu
Bulletin of the American Astronomical Society, 37 #2
© 2005. The American Astronomical Soceity.