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Hypervelocity star candidates in Gaia DR1/TGAS

Published online by Cambridge University Press:  07 March 2018

T. Marchetti Open the ORCID record for T. Marchetti [Opens in a new window] ,
E. M. Rossi ,
G. Kordopatis ,
A. G. A. Brown ,
A. Rimoldi ,
E. Starkenburg ,
K. Youakim  and
R. Ashley
T. Marchetti
Affiliation:
Leiden Observatory, Leiden University, PO Box 9513 2300 RA Leiden, the Netherlands email: [email protected]
E. M. Rossi
Affiliation:
Leiden Observatory, Leiden University, PO Box 9513 2300 RA Leiden, the Netherlands email: [email protected]
G. Kordopatis
Affiliation:
Université Côte d'Azur, Observatoire de la Côte d'Azur, CNRS, Laboratoire Lagrange, France
A. G. A. Brown
Affiliation:
Leiden Observatory, Leiden University, PO Box 9513 2300 RA Leiden, the Netherlands email: [email protected]
A. Rimoldi
Affiliation:
Leiden Observatory, Leiden University, PO Box 9513 2300 RA Leiden, the Netherlands email: [email protected]
E. Starkenburg
Affiliation:
Leibniz-Institut fur Astrophysik Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany
K. Youakim
Affiliation:
Leibniz-Institut fur Astrophysik Potsdam (AIP), An der Sternwarte 16, 14482 Potsdam, Germany
R. Ashley
Affiliation:
Department of Physics, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK
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Abstract

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Hypervelocity stars (HVSs) are characterized by a total velocity in excess of the Galactic escape speed, and with trajectories consistent with coming from the Galactic Centre. We apply a novel data mining routine, an artificial neural network, to discover HVSs in the TGAS subset of the first data release of the Gaia satellite, using only the astrometry of the stars. We find 80 stars with a predicted probability >90% of being HVSs, and we retrieved radial velocities for 47 of those. We discover 14 objects with a total velocity in the Galactic rest frame >400 km s−1, and 5 of these have a probability >50% of being unbound from the Milky Way. Tracing back orbits in different Galactic potentials, we discover 1 HVS candidate, 5 bound HVS candidates, and 5 runaway star candidates with remarkably high velocities, between 400 and 780 km s−1. We wait for future Gaia releases to confirm the goodness of our sample and to increase the number of HVS candidates.

Keywords

AstrometryThe Galaxy: kinematics and dynamicsThe Galaxy: stellar content
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 12 , Symposium S330: Astrometry and Astrophysics in the Gaia sky , April 2017 , pp. 181 - 184
Copyright
Copyright © International Astronomical Union 2018 

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