Hypervelocity Stars II. The Bound Population
Abstract
Hypervelocity stars (HVSs) are stars ejected completely out of the Milky Way by three-body interactions with the massive black hole in the Galactic center. We describe 643 new spectroscopic observations from our targeted survey for HVSs. We find a significant (3.5 sigma) excess of B-type stars with large velocities +275<v_rf<450 km/s and distances d>10 kpc that are most plausibly explained as a new class of HVSs: stars ejected from the Galactic center on bound orbits. If a Galactic center ejection origin is correct, the distribution of HVSs on the sky should be anisotropic for a survey complete to a fixed limiting apparent magnitude. The unbound HVSs in our survey have a marginally anisotropic distribution on the sky, consistent with the Galactic center ejection picture.
Cite
@article{arxiv.astro-ph/0701600,
title = {Hypervelocity Stars II. The Bound Population},
author = {Warren R. Brown and Margaret J. Geller and Scott J. Kenyon and Michael J. Kurtz and Benjamin C. Bromley},
journal= {arXiv preprint arXiv:astro-ph/0701600},
year = {2011}
}
Comments
8 pages, accepted to ApJ