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arXiv · 2605.28758

Cluster-centric trends in bar size and pattern speed: the case of Abell 2199

Chandan Watts·Sudhanshu Barway·Mousumi Das·Ewa L. Lokas
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Abstract

We investigate how the environment of a dynamically unrelaxed galaxy cluster influences the structure and dynamics of stellar bars. In particular, we examine cluster-centric variations in normalised bar size and bar pattern speed in Abell 2199. Our analysis is based on 578 spectroscopically confirmed members of Abell 2199, including a master sample of 325 galaxies with homogeneous stellar mass and star formation rate measurements. We identify 39 barred galaxies and measure their structural properties using isophotal ellipse fitting and three-component (bulge+disc+bar) photometric decompositions. For 22 barred galaxies with MaNGA integral-field spectroscopy, we estimate bar pattern speeds using the Tremaine-Weinberg method, obtaining robust measurements for 12 galaxies. Stellar population age and projected specific angular momentum are analysed using $D4000_{R_{\mathrm{e}}}$ and $λ_{R_{\mathrm{e}}}$ from the MaNGA Pipe3D catalogue. Abell2199 exhibits star formation-density and morphology-density relations despite its non-relaxed dynamical state. Early-type spiral (ETS) barred galaxies show systematic cluster-centric variations in normalised bar size, with relatively larger bars towards the cluster centre and smaller bars at intermediate radii. A corresponding variation in bar pattern speed with cluster-centric distance is also observed. These trends motivate a division at $\sim$0.5$R_{\mathrm{vir}}$, within which morphology-dependent environmental signatures become clearer, as barred galaxies in the inner region tend to host older stellar populations and lower projected angular momentum than those in the outskirts, with ETS+Bar galaxies retaining higher angular momentum compared to S0+Bar galaxies at comparable radii.

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Chandan Watts, Sudhanshu Barway, Mousumi Das, Ewa L. Lokas. 2026-05-27. Cluster-centric trends in bar size and pattern speed: the case of Abell 2199. https://arxiv.org/abs/2605.28758

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