------------------------------------------------------------------------ HVBS.tex, ApJL, in press Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed X-MailScanner-Information: Please contact the postmaster@aoc.nrao.edu for more information X-MailScanner: Found to be clean X-MailScanner-SpamCheck: not spam, SpamAssassin (not cached, score=0, required 5, autolearn=disabled) X-MailScanner-From: lyj@ucolick.org X-Spam-Status: No %arXiv:0707.1872 \documentstyle{article} (your LaTex file goes into the body of the email) \begin{document} \title{Hypervelocity binary stars: smoking gun of massive binary black holes} \author{Youjun Lu\altaffilmark{1}, Qingjuan Yu\altaffilmark{1}, \& D.\ N.\ C.\ Lin\altaffilmark{1,2}} \altaffiltext{1}{Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064, USA} \altaffiltext{2}{Kavli Institute of Astronomy and Astrophysics, Peking University, Beijing, China} \email{lyj, yqj, lin@ucolick.org} \begin{abstract} The hypervelocity stars recently found in the Galactic halo are expelled from the Galactic center through interactions between binary stars and the central massive black hole or between single stars and a hypothetical massive binary black hole. In this paper, we demonstrate that binary stars can be ejected out of the Galactic center with velocities up to $10^3\kms$, while preserving their integrity, through interactions with a massive binary black hole. Binary stars are unlikely to attain such high velocities via scattering by a single massive black hole or through any other mechanisms. Based on the above theoretical prediction, we propose a search for binary systems among the hypervelocity stars. Discovery of hypervelocity binary stars, even one, is a definitive evidence of the existence of a massive binary black hole in the Galactic center. \end{abstract} \keywords{black holes physics -- Galaxy:center -- stellar dynamics} \end{document}