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arXiv · 2603.02904

Spatial Property of Multiple Metallic Populations in the Tidal Stream of {\omega} Centauri

Shiru Zheng·Baitian Tang·Long Wang·Jose G. Fernandez-Trincado·Ruoyun Huang·Xia Li·XiaoDong Li
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Abstract

{\omega} Centauri, the remnant nucleus of an accreted dwarf galaxy, is a unique laboratory for studying complex stellar populations. The recently discovered Fimbulthul stream provides a fossil record of its ongoing tidal dissolution. In this work, we investigate the spatial distributions of metal-rich and metal-poor populations within {\omega} Centauri and its stream to constrain the cluster's formation history. Using synthetic photometry from Gaia DR3 XP spectra, we classify stars via a Support Vector Classifier (SVC). The spatial distributions are then compared to a scaling N-body simulation performed with the PeTar code. Our analysis reveals no significant radial gradient in population ratios within the cluster, though the metal-rich stars may be slightly more extended. The population ratio in the tidal stream is consistent with that of the present-day cluster, albeit with large uncertainties. Our simulation indicates that any initial radial gradient must have been shallow, with a maximum fraction difference less than 0.15. Both observational and dynamical results suggest that the metal-rich population is not formed centrally concentrated. By combining our results and existing literature, we propose a new formation scenario for {\omega} Centauri.

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Shiru Zheng, Baitian Tang, Long Wang, Jose G. Fernandez-Trincado, Ruoyun Huang, Xia Li, XiaoDong Li. 2026-03-03. Spatial Property of Multiple Metallic Populations in the Tidal Stream of {\omega} Centauri. https://arxiv.org/abs/2603.02904

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