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A JWST Project on 47 Tucanae: Kinematics, energy equipartition and anisotropy of multiple populations

Authors :
Ziliotto, T.
Milone, A. P.
Cordoni, G.
Aros, F. I.
Vesperini, E.
Lee, J. W.
Bellini, A.
Libralato, M.
Dondoglio, E.
Tailo, M.
Livernois, A.
Legnardi, M. V.
Mastrobuono-Battisti, A.
Lagioia, E.
Bortolan, E.
Muratore, F.
Marino, A. F.
Alves-Brito, A.
Renzini, A.
Publication Year :
2025

Abstract

Recent work with JWST has demonstrated its capability to identify and chemically characterize multiple populations in globular clusters down to the H-burning limit. In this study, we explore the kinematics of multiple populations in the globular cluster 47 Tucanae by combining data from JWST, HST, and Gaia. We analyzed velocity dispersion and anisotropy profiles from the cluster center out to $\sim$10$R_h$. Our findings indicate that while 1G stars are isotropic, 2G stars are significantly radially anisotropic. These results align with the predictions of simulations of the dynamical evolution of clusters where 2G stars are initially more centrally concentrated than 1G stars. Furthermore, we subdivided the 2G population into two subpopulations: $2G_A$ and $2G_B$, with the latter being more chemically extreme. We compared their dynamical profiles and found no significant differences. For the first time, we measured the degree of energy equipartition among the multiple populations of 47 Tucanae. Overall, within the analyzed radial range ($\sim$2-4$R_h$), both populations exhibit a low degree of energy equipartition. The most significant differences between 1G and 2G stars are observed in the tangential velocity component, where 2G stars are characterized by a stronger degree of energy equipartition than 1G stars. In the radial component, the behavior of 1G and 2G stars is more variable, with differences largely dependent on radius. Finally, our analysis reveals that the ratio of rotational velocity to velocity dispersion is larger for the 2G population, while 1G stars exhibit higher skewness in their tangential proper motions, providing further evidence of differences in the kinematic properties of the 1G and 2G populations.

Details

Database :
arXiv
Publication Type :
Report
Accession number :
edsarx.2502.03140
Document Type :
Working Paper