SEGUE-2 LIMITS ON METAL-RICH OLD-POPULATION HYPERVELOCITY STARS IN THE GALACTIC HALO

@article{Kollmeier2010SEGUE2LO,
  title={SEGUE-2 LIMITS ON METAL-RICH OLD-POPULATION HYPERVELOCITY STARS IN THE GALACTIC HALO},
  author={Juna A. Kollmeier and Andrew P. Gould and Constance M. Rockosi and Timothy C. Beers and Gillian R. Knapp and Jennifer A. Johnson and Heather L. Morrison and Paul Harding and Young Sun Lee and Benjamin Alan Weaver},
  journal={The Astrophysical Journal},
  year={2010},
  volume={723},
  pages={812 - 817}
}
We present new limits on the ejection of metal-rich old-population hypervelocity stars (HVSs) 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… 

19 low mass hypervelocity star candidates from the first data release of the LAMOST survey

Hypervelocity stars are believed to be ejected out from the Galactic center through dynamical interactions between (binary) stars and the central supermassive black hole(s). In this paper, we report

METAL-POOR HYPERVELOCITY STAR CANDIDATES FROM THE SLOAN DIGITAL SKY SURVEY

Hypervelocity stars are believed to be ejected out from the Galactic center (GC) through dynamical interactions of (binary) stars with the central massive black hole(s). In this Letter, we report 13

Old, Metal-poor Extreme Velocity Stars in the Solar Neighborhood

We report the discovery of 30 stars with extreme space velocities (≳480 ) in the Gaia-DR2 archive. These stars are a subset of 1743 stars with high-precision parallax, large tangential velocity (vtan

HYPERVELOCITY STAR CANDIDATES IN THE SEGUE G AND K DWARF SAMPLE

We present 20 candidate hypervelocity stars from the Sloan Extension for Galactic Understanding and Exploration (SEGUE) G and K dwarf samples. Previous searches for hypervelocity stars have only

THE VELOCITY DISTRIBUTION OF HYPERVELOCITY STARS

We consider the process of stellar binaries tidally disrupted by a supermassive black hole (BH). For highly eccentric orbits, as one star is ejected from the three-body system, the companion remains

Chemical abundances in a high velocity RR Lyrae star near the bulge

Low-mass, variable, high-velocity stars are interesting study cases for many aspects of Galactic structure and evolution. Until recently, the only known high- or hyper-velocity stars were young stars

Predicting the hypervelocity star population in Gaia

Hypervelocity stars (HVSs) are amongst the fastest objects in our Milky Way. These stars are predicted to come from the Galactic center (GC) and travel along unbound orbits across the Galaxy. In the

Characterizing the high-velocity stars of RAVE: the discovery of a metal-rich halo star born in the Galactic disc

We aim to characterize high-velocity (HiVel) stars in the solar vicinity both chemically and kinematically using the fourth data release of the RAdial Velocity Experiment (RAVE). We used a sample of

RED RUNAWAYS: HYPERVELOCITY STARS, HILLS EJECTA, AND OTHER OUTLIERS IN THE F-TO-M STAR REGIME

In this paper we analyze a sample of metal-rich (>−0.8 dex) main sequence stars in the extended solar neighborhood, investigating kinematic outliers from the background population. The data, which

Discovery of Two New Hypervelocity Stars from the LAMOST Spectroscopic Surveys

We report the discovery of two new unbound hypervelocity stars (HVSs) from the LAMOST spectroscopic surveys. They are, respectively, a B2V-type star of ∼7 M⊙ with a Galactic rest-frame radial

References

SHOWING 1-10 OF 40 REFERENCES

Hypervelocity Stars. II. The Bound Population

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

OLD-POPULATION HYPERVELOCITY STARS FROM THE GALACTIC CENTER: LIMITS FROM THE SLOAN DIGITAL SKY SURVEY

We present limits on the ejection of solar-metallicity (“metal-rich”) old-population hypervelocity stars (HVS) from a sample of over 290,000 stars selected from the Sloan Digital Sky Survey. We

Where Are the Old-Population Hypervelocity Stars?

To date, all of the reported hypervelocity stars (HVSs), which are believed to be ejected from the Galactic center, are blue and therefore almost certainly young. Old-population HVSs could be much

AN EXTREMELY TOP-HEAVY INITIAL MASS FUNCTION IN THE GALACTIC CENTER STELLAR DISKS

We present new observations of the nuclear star cluster in the central parsec of the Galaxy with the adaptive optics assisted, integral field spectrograph SINFONI on the ESO/VLT. Our work allows the

AN ALTERNATIVE ORIGIN FOR HYPERVELOCITY STARS

Halo stars with unusually high radial velocity (hypervelocity stars, or HVS) are thought to be stars unbound to the Milky Way that originate from the gravitational interaction of stellar systems with

"Ejection of hypervelocity stars from the Galactic Centre by intermediate-mass black holes"

We have performed N-body simulations of the formation of hypervelocity stars (HVS) in the centre of the Milky Way due to inspiralling intermediate-mass black holes (IMBHs). We considered IMBHs of

Hypervelocity Stars. III. The Space Density and Ejection History of Main-Sequence Stars from the Galactic Center

We report the discovery of three new unbound hypervelocity stars (HVSs), stars traveling with such extreme velocities that dynamical ejection from a massive black hole (MBH) is their only suggested

Ejection of High-Velocity Stars from the Galactic Center by an Inspiraling Intermediate-Mass Black Hole

The presence of young stars near Sgr A* remains unexplained. One idea for their origin posits that the stars were brought in by an intermediate-mass black hole (IMBH) that inspiraled into the

Ejection of Hypervelocity Stars by the (Binary) Black Hole in the Galactic Center

We study three processes that eject hypervelocity (>103 km s-1) stars from the Galactic center: (1) close encounters of two single stars, (2) tidal breakup of binary stars by the central black hole,

Discovery of an Unbound Hypervelocity Star in the Milky Way Halo

We have discovered a star, SDSS J090745.0+024507, leaving the Galaxy with a heliocentric radial velocity of 853 ± 12 km s-1, the largest velocity ever observed in the Milky Way halo. The star is