Skip to main content

Research Repository

Advanced Search

Co-formation of the disc and the stellar halo★

Belokurov, V.; Erkal, D.; Evans, NW.; Koposov, S.E.; Deason, A.J.

Co-formation of the disc and the stellar halo★ Thumbnail


Authors

V. Belokurov

D. Erkal

NW. Evans

S.E. Koposov



Abstract

Using a large sample of main sequence stars with 7D measurements supplied by Gaia and SDSS, we study the kinematic properties of the local (within ∼10 kpc from the Sun) stellar halo. We demonstrate that the halo’s velocity ellipsoid evolves strongly with metallicity. At the low-[Fe/H] end, the orbital anisotropy (the amount of motion in the radial direction compared with the tangential one) is mildly radial, with 0.2 <β< 0.4. For stars with [Fe/H] > −1.7, however, we measure extreme values of β∼ 0.9. Across the metallicity range considered, namely−3 < [Fe/H] < −1, the stellar halo’s spin is minimal, at the level of 20 1010M⊙ around the epoch of the Galactic disc formation, between 8 and 11 Gyr ago. The radical halo anisotropy is the result of the dramatic radialization of the massive progenitor’s orbit, amplified by the action of the growing disc.

Citation

Belokurov, V., Erkal, D., Evans, N., Koposov, S., & Deason, A. (2018). Co-formation of the disc and the stellar halo★. Monthly Notices of the Royal Astronomical Society, 478(1), 611-619. https://doi.org/10.1093/mnras/sty982

Journal Article Type Article
Acceptance Date Apr 17, 2018
Online Publication Date Jun 2, 2018
Publication Date Jul 21, 2018
Deposit Date Jun 27, 2018
Publicly Available Date Mar 28, 2024
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 478
Issue 1
Pages 611-619
DOI https://doi.org/10.1093/mnras/sty982

Files

Published Journal Article (1.3 Mb)
PDF

Copyright Statement
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.





You might also like



Downloadable Citations