The browser you are using is not supported by this website. All versions of Internet Explorer are no longer supported, either by us or Microsoft (read more here: https://www.microsoft.com/en-us/microsoft-365/windows/end-of-ie-support).

Please use a modern browser to fully experience our website, such as the newest versions of Edge, Chrome, Firefox or Safari etc.

Thomas Bensby. Profile photo.

Thomas Bensby

Senior lecturer

Thomas Bensby. Profile photo.

The hunt for the Milky Way's accreted disc

Author

  • Gregory Ruchti
  • Justin I. Read
  • Sofia Feltzing
  • Antonio Pipino
  • Thomas Bensby

Summary, in English

The Milky Way is expected to host an accreted disc of stars and dark matter. This forms as massive greater than or similar to 1 : 10 mergers are preferentially dragged towards the disc plane by dynamical friction and then tidally shredded. The accreted disc likely contributes only a tiny fraction of the MilkyWay's thin and thick stellar disc. However, it is interesting because (i) its associated 'dark disc' has important implications for experiments hoping to detect a dark matter particle in the laboratory; and (ii) the presence or absence of such a disc constrains the merger history of our Galaxy. In this work, we develop a chemodynamical template to hunt for the accreted disc. We apply our template to the high-resolution spectroscopic sample from Ruchti et al., finding at present no evidence for accreted disc stars. Our results are consistent with a quiescent Milky Way with no greater than or similar to 1 : 10 mergers since the disc formed and a correspondingly light ` dark disc'. However, we caution that while our method can robustly identify accreted stars, our incomplete stellar sample makes it more challenging to definitively rule them out. Larger unbiased stellar samples will be required for this.

Department/s

  • Lund Observatory

Publishing year

2014

Language

English

Pages

515-526

Publication/Series

Monthly Notices of the Royal Astronomical Society

Volume

444

Issue

1

Document type

Journal article

Publisher

Oxford University Press

Topic

  • Astronomy, Astrophysics and Cosmology

Keywords

  • stars: abundances
  • stars: kinematics and dynamics
  • Galaxy: disc
  • Galaxy:
  • evolution
  • Galaxy: formation
  • Galaxy: kinematics and dynamics

Status

Published

ISBN/ISSN/Other

  • ISSN: 1365-2966