A Successful Targeted Search for Hypervelocity Stars

Abstract

Hypervelocity stars (HVSs) travel with velocities so extreme that dynamical ejection from a massive black hole is their only suggested origin. Following our discovery of the first HVS, we have undertaken a dedicated survey for more HVSs in the Galactic halo and present here the resulting discovery of two new HVSs: SDSS J091301.0+305120 and SDSS J091759.5+672238, traveling with Galactic rest-frame velocities at least +558+-12 and +638+-12 km/s, respectively. Assuming the HVSs are B8 main sequence stars, they are at distances ~75 and ~55 kpc, respectively, and have travel times from the Galactic Center consistent with their lifetimes. The existence of two B8 HVSs in our 1900 deg^2 survey, combined with the Yu & Tremaine HVS rate estimates, is consistent with HVSs drawn from a standard initial mass function but inconsistent with HVS drawn from a truncated mass function like the one in the top-heavy Arches cluster. The travel times of the five currently known HVSs provide no evidence for a burst of HVSs from a major in-fall event at the Galactic Center in the last \~160 Myr.

5 pages, submitted to ApJ Letters

References in corpus (22)

• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• The USNO-B Catalog
• The Fourth Data Release of the Sloan Digital Sky Survey
• SINFONI in the Galactic Center: young stars and IR flares in the central light month
• RVSAO 2.0: Digital Redshifts and Radial Velocities
• Ejection of hypervelocity stars by the (binary) black hole(s) in the Galactic center
• Identification of A-colored Stars and Structure in the Halo of the Milky Way from SDSS Commissioning Data
• The Present and Future Mass of the Milky Way Halo
• Discovery of an Unbound Hyper-Velocity Star in the Milky Way Halo
• The Galactic Center He I Stars: Remains of a Dissolved Young Cluster?
• US 708 - An unbound hyper-velocity subluminous O star
• HE 0437-5439 -- an unbound hyper-velocity main-sequence B-type star
• The need for a second black hole at the Galactic center
• Probing the Shape of the Galactic Halo with Hyper-Velocity Stars
• The Arches Cluster - Evidence for a Truncated Mass Function?
• Dynamical Friction on Star Clusters near the Galactic Center
• Variable Stars in Leo A: RR Lyraes, Short-period Cepheids, and Implications on Stellar Content
• Three-body encounters in the Galactic centre: the origin of the hypervelocity star SDSS J090745.0+024507
• Modeling complete distributions with incomplete observations: The velocity ellipsoid from Hipparcos data
• Distant field BHB stars and the mass of the Galaxy I: Classification of halo A-type stars
• The Hypervelocity Star SDSS J090745.0+024507 is a Short-Period Variable
• The Century Survey Galactic Halo Project I: Stellar Spectral Analysis

Cited by in corpus (79)

• The Galactic Center Massive Black Hole and Nuclear Star Cluster
• LAMOST Experiment for Galactic Understanding and Exploration (LEGUE) The survey science plan
• Gravitational waves from scattering of stellar-mass black holes in galactic nuclei
• Massive perturber-driven interactions of stars with a massive black hole
• Mass Deficits, Stalling Radii, and the Merger Histories of Elliptical Galaxies
• Interaction of massive black hole binaries with their stellar environment: I. Ejection of hypervelocity stars
• The ELM Survey. I. A Complete Sample of Extremely Low Mass White Dwarfs
• High-resolution UVES/VLT spectra of white dwarfs observed for the ESO SN Ia Progenitor Survey. III. DA white dwarfs
• Hypervelocity Stars: Predicting the Spectrum of Ejection Velocities
• 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
• Taking the Measure of the Universe: Precision Astrometry with SIM PlanetQuest
• Hypervelocity Stars. I. The Spectroscopic Survey
• Hypervelocity Stars: From the Galactic Center to the Halo
• MMT Hypervelocity Star Survey
• The ELM Survey. V. Merging Massive White Dwarf Binaries
• Hyper Velocity Stars and the Restricted Parabolic 3-body Problem
• Maximum speed of hypervelocity stars ejected from binaries
• The ELM Survey. III. A Successful Targeted Survey for Extremely Low Mass White Dwarfs
• Velocity Dispersion Profile of the Milky Way Halo
• Hypervelocity Stars III. The Space Density and Ejection History of Main Sequence Stars from the Galactic Center
• Hypervelocity Stars II. The Bound Population
• Gaia and the Galactic Center Origin of Hypervelocity Stars
• The First Hypervelocity Star from the LAMOST Survey
• Hypervelocity stars and the environment of Sgr A*
• Kinematics of hypervelocity stars in the triaxial halo of the Milky Way
• Production of Hypervelocity Stars through Encounters with Stellar-Mass Black Holes in the Galactic Centre
• Hypervelocity runaways from the Large Magellanic Cloud
• Dynamical and evolutionary constraints on the nature and origin of hypervelocity stars
• Tracing intermediate-mass black holes in the Galactic Centre
• MMT Hypervelocity Star Survey. II. Five New Unbound Stars
• Predicted Space Motions for Hypervelocity and Runaway Stars: Proper Motions and Radial Velocities for the GAIA Era
• Hypervelocity binary stars: smoking gun of massive binary black holes
• The Anisotropic Spatial Distribution of Hypervelocity Stars
• Proper Motions and Trajectories for 16 Extreme Runaway and Hypervelocity Stars
• Identifying Contributions to the Stellar Halo from Accreted, Kicked-Out, and In Situ Populations
• Hypervelocity Collisions of Binary Stars at the Galactic Centre
• Runaway Stars, Hypervelocity Stars, and Radial Velocity Surveys
• Hyperfast pulsars as the remnants of massive stars ejected from young star clusters
• Nearby high-speed stars in Gaia DR2
• A Hybrid N-Body Code Incorporating Algorithmic Regularization and Post-Newtonian Forces
• 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
• Gaia DR3 in 6D: The search for fast hypervelocity stars and constraints on the Galactic Centre environment
• Hypervelocity Stars from the Andromeda Galaxy
• MMT Extremely Metal Poor Galaxy Survey I. An Efficient Technique to Identify Metal Poor Galaxies
• Where are the Old-Population High Velocity Stars?
• Hypervelocity Stars from a Supermassive Black Hole-Intermediate-mass Black Hole binary
• Ejection of hypervelocity binary stars by a black hole of intermediate mass orbiting Sgr A*
• The secular tidal disruption of stars by low-mass Super Massive Black Holes secondaries in galactic nuclei
• 'Slow' and Fast Rotators among Hypervelocity Stars
• CD-62\degree1346: an extreme halo or hypervelocity CH~star?
• Hypervelocity stars from star clusters hosting Intermediate-Mass Black Holes
• Stellar Accelerations and the Galactic Gravitational Field
• The dearth of nuclear star clusters in bright galaxies
• Hypervelocity Stars in the Gaia era. Revisiting the most extreme stars from the MMT survey
• The Evolution of Helium Star Plus Carbon-Oxygen White Dwarf Binary Systems and Implications for Diverse Stellar Transients and Hypervelocity Stars
• The Galactic potential and the asymmetric distribution of hypervelocity stars
• Impact of the Galactic Disk and Large Magellanic Cloud on the Trajectories of Hypervelocity Stars Ejected from the Galactic Center
• Hypervelocity Planets and Transits Around Hypervelocity Stars
• Tidal breakup of triple stars in the Galactic Centre
• Constraints on the Galactic Centre environment from Gaia hypervelocity stars
• Kinematics in galactic tidal tails - A source for Hypervelocity stars?
• Comparing hypervelocity star populations from the Large Magellanic Cloud and the Milky Way
• Constraints on the Galactic Centre environment from \textit{Gaia} hypervelocity stars III: Insights on a possible companion to Sgr A*
• Constraints on the Galactic Centre environment from Gaia hypervelocity stars II: The evolved population
• The nature of hypervelocity stars as inferred from their galactic trajectories
• Hypervelocity star candidates from Gaia DR2 and DR3 proper motions and parallaxes
• High proper motion X-ray binaries from the Yale Southern Proper Motion Survey
• The Origin of HVS17, an Unbound Main Sequence B Star at 50 kpc
• Astrophysics in 2006
• Tidal breakup of quadruple stars in the Galactic Centre
• Probing the shape of the Milky Way dark matter halo with hypervelocity stars: a new method
• Identifying Star Streams in the Milky Way Halo
• Massive perturbers in the galactic center
• The HYPERMUCHFUSS Campaign -- an undiscovered high velocity population
• Searching for new Hypervelocity Stars with Gaia DR3 and VLT/FORS2 Spectroscopy
• A hypervelocity star from the Large Magellanic Cloud
• Ejection of Hyper-Velocity Stars from the Galactic Centre by Intermediate-Mass Black Holes