| Issue |
A&A
Volume 670, February 2023
|
|
|---|---|---|
| Article Number | L2 | |
| Number of page(s) | 7 | |
| Section | Letters to the Editor | |
| DOI | https://doi.org/10.1051/0004-6361/202244546 | |
| Published online | 27 January 2023 | |
Letter to the Editor
Gaia DR3 view of dynamical substructure in the stellar halo near the Sun⋆
Kapteyn Astronomical Institute, University of Groningen, Landleven 12, 9747 AD Groningen, The Netherlands
e-mail: dodd@astro.rug.nl
Received:
19
July
2022
Accepted:
2
December
2022
Context. Debris from past merger events is expected and also known, to some extent, to populate the stellar halo near the Sun.
Aims. We aim to identify and characterise such merger debris using Gaia DR3 data supplemented with metallicity and chemical abundance data from LAMOST LRS and APOGEE for halo stars within 2.5 kpc from the Sun.
Methods. We utilised a single linkage-based clustering algorithm to identify over-densities in the integrals of motion space that could be due to merger debris. Combined with metallicity information and chemical abundances, we characterised these statistically significant over-densities.
Results. We find that the local stellar halo contains seven main dynamical groups, with some of them shown to be in situ and some of accreted origin, most of which are already known. We report the discovery of a new substructure, which we dubbed ED-1. In addition, we find evidence for 11 independent smaller clumps, 5 of which are new: ED-2, 3, 4, 5, and 6, and typically rather tight dynamically. We identify their narrow range of metallicities, along with their abundances when available, as well as their locations in the integrals of motion space, which are suggestive of an accreted origin.
Conclusions. The local halo contains an important amount of substructure of both in situ and accreted origins.
Key words: Galaxy: kinematics and dynamics / Galaxy: halo / Galaxy: formation
The catalogue used in this paper is only available at the CDS via anonymous ftp to cdsarc.cds.unistra.fr (130.79.128.5) or via https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/670/L2
© The Authors 2023
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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