| Issue |
A&A
Volume 688, August 2024
|
|
|---|---|---|
| Article Number | A133 | |
| Number of page(s) | 10 | |
| Section | Galactic structure, stellar clusters and populations | |
| DOI | https://doi.org/10.1051/0004-6361/202450147 | |
| Published online | 13 August 2024 | |
The ESO-VLT MIKiS survey reloaded: The internal kinematics of the core of M75⋆,⋆⋆
1
Dipartimento di Fisica e Astronomia, Università di Bologna, Via Gobetti 93/2, 40129 Bologna, Italy
e-mail: silvia.leanza2@unibo.it
2
INAF – Osservatorio di Astrofisica e Scienze dello Spazio di Bologna, Via Gobetti 93/3, 40129 Bologna, Italy
3
Department of Astronomy, Indiana University, Bloomington, IN 47401, USA
4
European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching bei Munchen, Germany
5
Excellence Cluster ORIGINS, Boltzmann-Strasse 2, 85748 Garching Bei Munchen, Germany
Received:
27
March
2024
Accepted:
17
May
2024
We present the results of a study aimed at characterizing the kinematics of the inner regions of the halo globular cluster M75 (NGC 6864) based on data acquired as part of the ESO-VLT Multi-Instrument Kinematic Survey (MIKiS) of Galactic globular clusters. Our analysis includes the first determination of the line-of-sight velocity dispersion profile in the core region of M75. By using MUSE/NFM observations, we obtained a sample of ∼1900 radial velocity measurements from individual stars located within 16″ from the cluster center (corresponding to about r < 3 rc, where rc is the estimated core radius of the system). After an appropriate selection of the most accurate velocity measures, we determined the innermost portion of the velocity dispersion profile, finding that it is characterized by a constant behavior and a central velocity dispersion of σ0 ∼ 9 km s−1. The simultaneous King model fitting to the projected velocity dispersion and density profiles allowed us to check and update previous determinations of the main structural parameters of the system. We also detected a mild hint of rotation in the central ∼7″ from the center, with an amplitude of just ∼1.0 km s−1 and a rotation axis position angle of PA0 = 174°. Intriguingly, the position angle is consistent with that previously quoted for the suspected rotation signal in the outer region of the cluster. Taking advantage of the high quality of the photometric catalog used for the analysis of the MUSE spectra, we also provide updated estimates of the cluster distance, age, and reddening.
Key words: techniques: radial velocities / techniques: spectroscopic / stars: kinematics and dynamics / globular clusters: individual: M75 (NGC 6864)
The kinematic catalog, including the radial velocities and the corresponding errors obtained in this work, is available at the CDS via anonymous ftp to cdsarc.cds.unistra.fr (130.79.128.5) or via https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/688/A133
© The Authors 2024
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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