Skip to Main content Skip to Navigation
New interface
Journal articles

A Deep View into the Nucleus of the Sagittarius Dwarf Spheroidal Galaxy with MUSE. III. Discrete Multicomponent Population-dynamical Models Based on the Jeans Equations

Abstract : We present comprehensive multicomponent dynamical models of M54 (NGC 6715), the nuclear star cluster of the Sagittarius (Sgr) dwarf galaxy, which is undergoing a tidal disruption in the Milky Way halo. Previous papers in this series used a large MUSE mosaic data set to identify multiple stellar populations in the system and study their kinematic differences. Here, we use Jeans-based dynamical models that fit the population properties (mean age and metallicity), spatial distributions, and kinematics simultaneously. They provide a solid physical explanation for our previous findings. Population-dynamical models deliver a comprehensive view of the whole system, and allow us to disentangle the different stellar populations. We explore their dynamical interplay and confirm our previous findings about the build-up of Sgr's nuclear cluster via contributions from globular cluster stars, Sgr inner field stars, and in situ star formation. We explore various parameterizations of the gravitational potential and show the importance of a radially varying mass-to-light ratio for the proper treatment of the mass profile. We find a total dynamical mass within M54's tidal radius (~75 pc) of 1.60 ± 0.07 × 106 M in excellent agreement with N-body simulations. Metal-poor globular cluster stars contribute about 65% of the total mass or 1.04 ± 0.05 × 106 M . Metal-rich stars can be further divided into young and intermediate-age populations, which contribute 0.32 ± 0.02 × 106 M (20%) and 0.24 ± 0.02 × 106 M (15%), respectively. Our population-dynamical models successfully distinguish the different stellar populations in Sgr's nucleus because of their different spatial distributions, ages, metallicities, and kinematic features.
Complete list of metadata

https://hal-insu.archives-ouvertes.fr/insu-03865900
Contributor : Olivier Hauss Connect in order to contact the contributor
Submitted on : Wednesday, November 23, 2022 - 6:52:08 AM
Last modification on : Wednesday, November 23, 2022 - 6:52:09 AM

File

Kacharov_2022_ApJ_939_118.pdf
Publisher files allowed on an open archive

Licence


Distributed under a Creative Commons Attribution 4.0 International License

Identifiers

Collections

Citation

Nikolay Kacharov, Mayte Alfaro-Cuello, Nadine Neumayer, Nora Lützgendorf, Laura L. Watkins, et al.. A Deep View into the Nucleus of the Sagittarius Dwarf Spheroidal Galaxy with MUSE. III. Discrete Multicomponent Population-dynamical Models Based on the Jeans Equations. The Astrophysical Journal, 2022, 939, ⟨10.3847/1538-4357/ac9280⟩. ⟨insu-03865900⟩

Share

Metrics

Record views

0

Files downloads

0