Bar-induced migration of ω Centauri away from Gaia Sausage-Enceladus
Abstract
The globular cluster ω Cen has been suggested to have originated in the Gaia Sausage-Enceladus (GSE) merger event, possibly as its nuclear star cluster. However, the present-day orbits of ω Cen and the GSE debris are very different. We investigate the scenario in which ω Cen originated in the GSE and migrated to its current position due to perturbations from the Galactic bar. The [α/M] distributions of stars located between the GSE debris and ω Cen in (Lz,E) space tentatively support this scenario, but are not conclusive. We run simulations of the GSE debris and ω Cen in a realistic Milky Way potential with a decelerating bar at various present-day pattern speeds. We find that ω Cen can indeed be traced back to the phase space region occupied by the GSE debris. However, this would likely require a pattern speed of Ωb≲26 km s−1 kpc−1, which is much lower than most recent estimates. We conclude that a GSE origin for ω Cen is dynamically and chemically plausible, but only with a re-evaluation of the current consensus on the bar's pattern speed.
Versions
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BibTeX
@misc{dillamore2026barinduced,
title = {{Bar-induced migration of $ω$ Centauri away from Gaia Sausage-Enceladus}},
author = {Adam M. Dillamore and Hanyuan Zhang and Vasily Belokurov},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2606.12516},
eprint = {2606.12516},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2606.12516},
}
RIS
TY - UNPB
TI - Bar-induced migration of ω Centauri away from Gaia Sausage-Enceladus
AU - Adam M. Dillamore
AU - Hanyuan Zhang
AU - Vasily Belokurov
PY - 2026
DA - 2026/09/01
PB - arXiv
DO - 10.48550/arxiv.2606.12516
UR - https://arxiv.org/abs/2606.12516
AB - The globular cluster ω Cen has been suggested to have originated in the Gaia Sausage-Enceladus (GSE) merger event, possibly as its nuclear star cluster. However, the present-day orbits of ω Cen and the GSE debris are very different. We investigate the scenario in which ω Cen originated in the GSE and migrated to its current position due to perturbations from the Galactic bar. The [α/M] distributions of stars located between the GSE debris and ω Cen in (L_z,E) space tentatively support this scenario, but are not conclusive. We run simulations of the GSE debris and ω Cen in a realistic Milky Way potential with a decelerating bar at various present-day pattern speeds. We find that ω Cen can indeed be traced back to the phase space region occupied by the GSE debris. However, this would likely require a pattern speed of Ω_b≲26 km s^−1 kpc^−1, which is much lower than most recent estimates. We conclude that a GSE origin for ω Cen is dynamically and chemically plausible, but only with a re-evaluation of the current consensus on the bar's pattern speed.
ER -