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arXiv · 1008.2384

SEGUE-2 Limits on Metal-Rich Old-Population Hypervelocity Stars In the Galactic Halo

Juna A. Kollmeier·Andrew Gould·Constance Rockosi·Timothy C. Beers·Gillian Knapp·Jennifer A. Johnson·Heather Morrison·Paul Harding·Young Sun Lee·Benjamin A. Weaver
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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.

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Juna A. Kollmeier, Andrew Gould, Constance Rockosi, Timothy C. Beers, Gillian Knapp, Jennifer A. Johnson, Heather Morrison, Paul Harding, Young Sun Lee, Benjamin A. Weaver. 2010-08-13. SEGUE-2 Limits on Metal-Rich Old-Population Hypervelocity Stars In the Galactic Halo. https://doi.org/10.1088/0004-637x%2F723%2F1%2F812

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