MMT Hypervelocity Star Survey

Abstract

We describe a new survey for unbound hypervelocity stars (HVSs), stars traveling with such extreme velocities that dynamical ejection from a massive black hole (MBH) is their most likely origin. We investigate the possible contribution of unbound runaway stars, and show that the physical properties of binaries constrain low mass runaways to bound velocities. We measure radial velocities for HVS candidates with the colors of early A-type and late B-type stars. We report the discovery of 6 unbound HVSs with velocities and distances exceeding the conservative escape velocity estimate of Kenyon and collaborators. We additionally report 4 possibly unbound HVSs with velocities and distances exceeding the lower escape velocity estimate of Xue and collaborators. These discoveries increase the number of known HVSs by 60%-100%. Other survey objects include 19 newly identified z~2.4 quasars. One of the HVSs may be a horizontal branch star, consistent with the number of evolved HVSs predicted by Galactic center ejection models. Finding more evolved HVSs will one day allow a probe of the low-mass regime of HVSs and will constrain the mass function of stars in the Galactic center.

10 pages, accepted to ApJ with minor revisions

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Cited by in corpus (86)

• The Galactic Center Massive Black Hole and Nuclear Star Cluster
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• The distribution of dark matter in galaxies
• The ELM Survey. I. A Complete Sample of Extremely Low Mass White Dwarfs
• The properties of dynamically ejected runaway and hyper-runaway stars
• MMT Hypervelocity Star Survey III: A Complete Survey of Faint B-type Stars in the Northern Milky Way Halo
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• The mass of our Milky Way
• Twelve years of spectroscopic monitoring in the Galactic Center: the closest look at S-stars near the black hole
• On the origin of high-velocity runaway stars
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• The nuclear cluster of the Milky Way: Our primary testbed for the interaction of a dense star cluster with a massive black hole
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• Maximum speed of hypervelocity stars ejected from binaries
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• Velocity Dispersion Profile of the Milky Way Halo
• Gaia and the Galactic Center Origin of Hypervelocity Stars
• Tidal break-up of binary stars at the Galactic center and its consequences
• Hypervelocity runaways from the Large Magellanic Cloud
• MMT Hypervelocity Star Survey. II. Five New Unbound Stars
• Tidal breakup of binary stars at the Galactic Center. II. Hydrodynamic simulations
• Predicted Space Motions for Hypervelocity and Runaway Stars: Proper Motions and Radial Velocities for the GAIA Era
• High velocity stars from close interaction of a globular cluster and a super massive black hole
• The interaction of core-collapse supernova ejecta with a companion star
• Characterizing the High-Velocity Stars of RAVE: The Discovery of a Metal-Rich Halo Star Born in the Galactic Disk
• S-stars in the Galactic center and hypervelocity stars in the Galactic halo: two faces of the tidal breakup of stellar binaries by the central massive black hole?
• Proper Motions and Trajectories for 16 Extreme Runaway and Hypervelocity Stars
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• The Velocity Distribution of Hypervelocity Stars
• On the spatial distribution and the origin of hypervelocity stars
• Runaway Stars, Hypervelocity Stars, and Radial Velocity Surveys
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• The Hyper-MUCHFUSS project: probing the Galactic halo with sdB stars
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• Hypervelocity Star Candidates in the SEGUE G & K Dwarf Sample
• Nearby high-speed stars in Gaia DR2
• Gaia DR3 in 6D: The search for fast hypervelocity stars and constraints on the Galactic Centre environment
• SDSS J013655.91+242546.0 - an A-type hyper-velocity star from the outskirts of the Galaxy
• A Galactic Center Origin for HE 0437-5439, the Hypervelocity Star near the Large Magellanic Cloud
• Core-Collapse Supernovae in Binaries as the Origin of Galactic Hyper-Runaway Stars
• Metal-poor hypervelocity star candidates from the Sloan Digital Sky Survey
• The Nearest High-Velocity Stars Revealed by LAMOST Data Release 1
• The Lagrange Equilibrium Points L_4 and L_5 in a Black Hole Binary System
• The sdA problem - II. Photometric and Spectroscopic Follow-up
• New nearby hypervelocity stars and their spatial distribution from Gaia DR2
• The Merger Rate of Extremely Low Mass White Dwarf Binaries: Links to the Formation of AM CVn Stars and Underluminous Supernovae
• CD-62\degree1346: an extreme halo or hypervelocity CH~star?
• The spatial and velocity distributions of hypervelocity stars
• The Shortest Period Detached Binary White Dwarf System
• The Runaway White Dwarf LP400-22 Has a Companion
• Hypervelocity Stars in the Gaia era. Revisiting the most extreme stars from the MMT survey
• A new Hyper-Runaway star discovered from LAMOST and GAIA: ejected almost in the galactic rotation direction
• Impact of the Galactic Disk and Large Magellanic Cloud on the Trajectories of Hypervelocity Stars Ejected from the Galactic Center
• The Galactic potential and the asymmetric distribution of hypervelocity stars
• Constraints on the Galactic Centre environment from Gaia hypervelocity stars
• Hypervelocity Planets and Transits Around Hypervelocity Stars
• The high velocity stars in the Local Stellar Halo from Gaia and LAMOST
• Discovery of A candidate Hypervelocity star originated from the Sagittarius Dwarf Spheroidal galaxy
• Kinematics in galactic tidal tails - A source for Hypervelocity stars?
• On the origins of extreme velocity stars as revealed by large-scale Galactic surveys
• Extreme mass ratio inspirals: perspectives for their detection
• Cosmology with Hypervelocity Stars
• Constraints on the Galactic Centre environment from \textit{Gaia} hypervelocity stars III: Insights on a possible companion to Sgr A*
• Comparing hypervelocity star populations from the Large Magellanic Cloud and the Milky Way
• The origin of high velocity stars from Gaia and LAMOST
• Constraints on the Galactic Centre environment from Gaia hypervelocity stars II: The evolved population
• Short-duration lensing events: I. wide-orbit planets? free-floating low-mass objects? or high-velocity stars?
• Tidal Disruption of Inclined or Eccentric Binaries by Massive Black Holes
• Supernovae without host galaxy? - Hypervelocity stars in foreign galaxies
• Hypervelocity star candidates from Gaia DR2 and DR3 proper motions and parallaxes
• Identifying High Metallicity M Giants at Intragroup Distances with SDSS
• The Origin of HVS17, an Unbound Main Sequence B Star at 50 kpc
• A halo blue straggler on a highly eccentric retrograde orbit
• The interaction of dark matter cusp with the baryon component in disk galaxies
• Can a Satellite Galaxy Merger Explain the Active Past of the Galactic Center?
• Binary Natal Kicks in the Galactic Center: X-ray Binaries, Hypervelocity Stars, and Gravitational Waves
• Probing the shape of the Milky Way dark matter halo with hypervelocity stars: a new method
• Stellar transits in active galactic nuclei
• Identifying Star Streams in the Milky Way Halo
• Probing modified Newtonian dynamics with hypervelocity stars
• A Star in the M31 Giant Stream: the Highest Negative Stellar Velocity Known
• Deviation in stellar trajectory induced by asymmetry in partial tidal disruption
• Three New Late-type Hypervelocity Star Candidates from Gaia DR2 with Refined Selection Criteria
• A Candidate High-Velocity Exoplanet System in the Galactic Bulge