SEGUE-2 Limits on Metal-Rich Old-Population Hypervelocity Stars In the Galactic Halo
Abstract
We present new limits on the ejection of metal-rich old-population hypervelocity stars from the Galactic center (GC) as probed by the SEGUE-2 survey. Our limits are a factor of 3-10 more stringent than previously reported, depending on stellar type. Compared to the known population of B-star ejectees, there can be no more than 30 times more metal-rich old-population F/G stars ejected from the GC. Because B stars comprise a tiny fraction of a normal stellar population, this places significant limits on a combination of the GC mass function and the ejection mechanism for hypervelocity stars. In the presence of a normal GC mass function, our results require an ejection mechanism that is about 5.5 times more efficient at ejecting B-stars compared to low-mass F/G stars.
Keywords
Cite
@article{arxiv.1008.2384,
title = {SEGUE-2 Limits on Metal-Rich Old-Population Hypervelocity Stars In the Galactic Halo},
author = {Juna A. Kollmeier and Andrew Gould and Constance Rockosi and Timothy C. Beers and Gillian Knapp and Jennifer A. Johnson and Heather Morrison and Paul Harding and Young Sun Lee and Benjamin A. Weaver},
journal= {arXiv preprint arXiv:1008.2384},
year = {2019}
}
Comments
18 pages including 5 figures; Submitted to ApJ