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A stellar census in globular clusters with MUSE: The contribution of rotation to cluster dynamics studied with 200 000 stars

Kamann, S, Husser, T-O, Dreizler, S, Emsellem, E, Weilbacher, PM, Martens, S, Bacon, R, Brok, MD, Giesers, B, Krajnović, D, Roth, MM, Wendt, M and Wisotzki, L (2017) A stellar census in globular clusters with MUSE: The contribution of rotation to cluster dynamics studied with 200 000 stars. Monthly Notices of the Royal Astronomical Society, 473 (4). pp. 5591-5616. ISSN 0035-8711

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Abstract

This is the first of a series of papers presenting the results from our survey of 25 Galactic globular clusters with the MUSE integral-field spectrograph. In combination with our dedicated algorithm for source deblending, MUSE provides unique multiplex capabilities in crowded stellar fields and allows us to acquire samples of up to 20 000 stars within the half-light radius of each cluster. The present paper focuses on the analysis of the internal dynamics of 22 out of the 25 clusters, using about 500 000 spectra of 200 000 individual stars. Thanks to the large stellar samples per cluster, we are able to perform a detailed analysis of the central rotation and dispersion fields using both radial profiles and two-dimensional maps. The velocity dispersion profiles we derive show a good general agreement with existing radial velocity studies but typically reach closer to the cluster centres. By comparison with proper motion data we derive or update the dynamical distance estimates to 14 clusters. Compared to previous dynamical distance estimates for 47 Tuc, our value is in much better agreement with other methods. We further find significant (>3sigma) rotation in the majority (13/22) of our clusters. Our analysis seems to confirm earlier findings of a link between rotation and the ellipticities of globular clusters. In addition, we find a correlation between the strengths of internal rotation and the relaxation times of the clusters, suggesting that the central rotation fields are relics of the cluster formation that are gradually dissipated via two-body relaxation.

Item Type: Article
Additional Information: This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2017 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Uncontrolled Keywords: astro-ph.GA; astro-ph.GA
Subjects: Q Science > QB Astronomy
Q Science > QC Physics
Divisions: Astrophysics Research Institute
Publisher: Oxford University Press
Related URLs:
Date Deposited: 25 Oct 2017 09:14
Last Modified: 21 Sep 2018 19:11
DOI or Identification number: 10.1093/mnras/stx2719
URI: http://researchonline.ljmu.ac.uk/id/eprint/7420

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