Goettgens, F, Kamann, S, Baumgardt, H, Dreizler, S, Giesers, B, Husser, T-O, den Brok, M, Fetick, R, Krajnović, D and Weilbacher, PM (2021) Central kinematics of the Galactic globular cluster M80. Monthly Notices of the Royal Astronomical Society, 507 (4). pp. 4788-4803. ISSN 0035-8711

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Abstract

We use spectra observed with the integral-field spectrograph Multi Unit Spectroscopic Explorer (MUSE) to reveal the central kinematics of the Galactic globular cluster Messier 80 (M80, NGC 6093). Using observations obtained with the recently commissioned narrow-field mode of MUSE, we are able to analyse 932 stars in the central 7.5 arcsec by 7.5 arcsec of the cluster for which no useful spectra previously existed. Mean radial velocities of individual stars derived from the spectra are compared to predictions from axisymmetric Jeans models, resulting in radial profiles of the velocity dispersion, the rotation amplitude, and the mass-to-light ratio. The new data allow us to search for an intermediate-mass black hole (IMBH) in the centre of the cluster. Our Jeans model finds two similarly probable solutions around different dynamical cluster centres. The first solution has a centre close to the photometric estimates available in the literature and does not need an IMBH to fit the observed kinematics. The second solution contains a location of the cluster centre that is offset by about 2.4 arcsec from the first one and it needs an IMBH mass of $4600^{+1700}_{-1400}~\text{M}_\odot {}$. N-body models support the existence of an IMBH in this cluster with a mass of up to 6000 M⊙ in this cluster, although models without an IMBH provide a better fit to the observed surface brightness profile. They further indicate that the cluster has lost nearly all stellar-mass black holes. We further discuss the detection of two potential high-velocity stars with radial velocities of 80-90 $\text{km}\, \text{s}^{-1}$ relative to the cluster mean.

Item Type:	Article
Additional Information:	This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2021 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.
Uncontrolled Keywords:	ACS SURVEY; Astronomy & Astrophysics; CATALOG; GAIA; globular clusters: individual: M80; MASS BLACK-HOLES; MODELS; MULTIPLE POPULATIONS; NO EVIDENCE; OMEGA CEN; Physical Sciences; PROFILES; Science & Technology; stars: kinematics and dynamics; techniques: imaging spectroscopy; TO-LIGHT RATIO; Science & Technology; Physical Sciences; Astronomy & Astrophysics; techniques: imaging spectroscopy; stars: kinematics and dynamics; globular clusters: individual: M80; MASS BLACK-HOLES; TO-LIGHT RATIO; ACS SURVEY; OMEGA CEN; MULTIPLE POPULATIONS; NO EVIDENCE; CATALOG; PROFILES; MODELS; GAIA; Science & Technology; Physical Sciences; Astronomy & Astrophysics; techniques: imaging spectroscopy; stars: kinematics and dynamics; globular clusters: individual: M80; MASS BLACK-HOLES; TO-LIGHT RATIO; ACS SURVEY; OMEGA CEN; MULTIPLE POPULATIONS; CATALOG; PROFILES; MODELS; GAIA; MUSE; astro-ph.GA; astro-ph.GA; astro-ph.SR; Astronomy & Astrophysics; 0201 Astronomical and Space Sciences
Subjects:	Q Science > QB Astronomy Q Science > QC Physics
Divisions:	Astrophysics Research Institute
Publisher:	Oxford University Press
SWORD Depositor:	A Symplectic
Date Deposited:	21 Sep 2022 11:27
Last Modified:	21 Sep 2022 11:30
DOI or ID number:	10.1093/mnras/stab2449
URI:	https://researchonline.ljmu.ac.uk/id/eprint/17647

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