Nitschai, MS, Neumayer, N, Häberle, M, Clontz, C, Seth, AC, Milone, AP, Alfaro-Cuello, M, Bellini, A, Dreizler, S, Feldmeier-Krause, A, Husser, TO, Kacharov, N, Kamann, S, Latour, M, Libralato, M, van de Ven, G, Voggel, K and Wang, Z (2024) oMEGACat. III. Multiband Photometry and Metallicities Reveal Spatially Well-mixed Populations within ω Centauri’s Half-light Radius. Astrophysical Journal, 970. ISSN 0004-637X

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Abstract

ω Centauri, the most massive globular cluster in the Milky Way, has long been suspected to be the stripped nucleus of a dwarf galaxy that fell into the Galaxy a long time ago. There is considerable evidence for this scenario including a large spread in metallicity and an unusually large number of distinct subpopulations seen in photometric studies. In this work, we use new Multi-Unit Spectroscopic Explorer spectroscopic and Hubble Space Telescope photometric catalogs to investigate the underlying metallicity distributions as well as the spatial variations of the populations within the cluster up to its half-light radius. Based on 11,050 member stars, the [M/H] distribution has a median of (−1.614 ± 0.003) dex and a large spread of ∼1.37 dex, reaching from −0.67 to −2.04 dex for 99.7% of the stars. In addition, we show the chromosome map of the cluster, which separates the red giant branch stars into different subpopulations, and analyze the subpopulations of the most metal-poor component. Finally, we do not find any metallicity gradient within the half-light radius, and the different subpopulations are well mixed.

Item Type:	Article
Uncontrolled Keywords:	0201 Astronomical and Space Sciences; 0202 Atomic, Molecular, Nuclear, Particle and Plasma Physics; 0306 Physical Chemistry (incl. Structural); Astronomy & Astrophysics
Subjects:	Q Science > QB Astronomy Q Science > QC Physics
Divisions:	Astrophysics Research Institute
Publisher:	American Astronomical Society
SWORD Depositor:	A Symplectic
Date Deposited:	25 Sep 2024 15:08
Last Modified:	25 Sep 2024 15:08
DOI or ID number:	10.3847/1538-4357/ad5289
URI:	https://researchonline.ljmu.ac.uk/id/eprint/24271

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