Trojan Globular Clusters: Radial Migration via Trapping in Bar Resonances

We search for globular clusters (GCs) trapped in resonances with the bar of the Milky Way (MW). By integrating their orbits in a potential with a decelerating bar, we select 10 whose orbits are significantly changed by its presence. Most of these are trapped in the corotation resonance, including M2...

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Bibliographic Details
Published in:Astrophysical journal. Letters 2024-08, Vol.971 (1), p.L4
Main Authors: Dillamore, Adam M., Monty, Stephanie, Belokurov, Vasily, Evans, N. Wyn
Format: Article
Language:English
Subjects:
Galactic bar
Globular clusters
Globular star clusters
Milky Way
Milky Way dynamics
Orbital resonances (celestial mechanics)
Orbits
Star clusters
Star formation
Stars
Stellar streams
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Summary:We search for globular clusters (GCs) trapped in resonances with the bar of the Milky Way (MW). By integrating their orbits in a potential with a decelerating bar, we select 10 whose orbits are significantly changed by its presence. Most of these are trapped in the corotation resonance, including M22 and 47 Tuc. The decelerating bar is capable of transporting these GCs to their current positions from much lower energies, angular momenta, and radii. Our results indicate that the bar is likely to have reshaped the MW’s GC system via its resonances. We also discuss implications for the origins of specific GCs, including the possible nuclear star cluster M22. Finally, we consider the effects of the bar on the tidal tails of a trapped GC by running simulations of stars stripped from 47 Tuc. Instead of forming narrow tails, the stripped stars make up a diffuse extended halo around the cluster, consistent with observations of 47 Tuc.
ISSN:2041-8205
2041-8213
DOI:10.3847/2041-8213/ad60c8