New candidate hypervelocity red clump stars in the inner Galactic bulge

A. Luna, T. Marchetti, M. Rejkuba, N. W.C. Leigh, J. Alonso-García, A. Valenzuela Navarro, D. Minniti, L. C. Smith

Research output: Contribution to journalArticlepeer-review

Abstract

We search for high-velocity stars in the inner region of the Galactic bulge using a selected sample of red clump stars. Some of those stars might be considered hypervelocity stars (HVSs). Even though the HVSs ejection relies on an interaction with the supermassive black hole (SMBH) at the centre of the Galaxy, there are no confirmed detections of HVSs in the inner region of our Galaxy. With the detection of HVSs, ejection mechanism models can be constrained by exploring the stellar dynamics in the Galactic centre through a recent stellar interaction with the SMBH. Based on a previously developed methodology by our group, we searched with a sample of preliminary data from version 2 of the Vista Variables in the Via Lactea (VVV) Infrared Astrometric Catalogue (VIRAC2) and Gaia DR3 data, including accurate optical and near-infrared proper motions. This search resulted in a sample of 46 stars with transverse velocities larger than the local escape velocity within the Galactic bulge, of which four are prime candidate HVSs with high-proper motions consistent with being ejections from the Galactic centre. Adding to that, we studied a sample of reddened stars without a Gaia DR3 counterpart and found 481 stars with transverse velocities larger than the local escape velocity, from which 65 stars have proper motions pointing out of the Galactic centre and are candidate HVSs. In total, we found 69 candidate HVSs pointing away from the Galactic centre with transverse velocities larger than the local escape velocity.

Original languageEnglish
Pages (from-to)5495-5510
Number of pages16
JournalMonthly Notices of the Royal Astronomical Society
Volume528
Issue number4
DOIs
Publication statusPublished - 1 Mar 2024

Keywords

  • dynamics
  • Galaxy: bulge
  • Galaxy: kinematics
  • proper motions
  • stars: peculiar (except chemically peculiar)
  • surveys

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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