A study of rotating globular clusters - the case of the old, metal-poor globular cluster NGC 4372

Abstract

Aims: We present the first in-depth study of the kinematic properties and derive the structural parameters of NGC 4372 based on the fit of a Plummer profile and a rotating, physical model. We explore the link between internal rotation to different cluster properties and together with similar studies of more GCs, we put these in the context of globular cluster formation and evolution. Methods: We present radial velocities for 131 cluster member stars measured from high-resolution FLAMES/GIRAFFE observations. Their membership to the GC is additionally confirmed from precise metallicity estimates. Using this kinematic data set we build a velocity dispersion profile and a systemic rotation curve. Additionally, we obtain an elliptical number density profile of NGC 4372 based on optical images using a MCMC fitting algorithm. From this we derive the cluster's half-light radius and ellipticity as r_h=3.4'+/-0.04' and e=0.08+/-0.01. Finally, we give a physical interpretation of the observed morphological and kinematic properties of this GC by fitting an axisymmetric, differentially rotating, dynamical model. Results: Our results show that NGC 4372 has an unusually high ratio of rotation amplitude to velocity dispersion (1.2 vs. 4.5 km/s) for its metallicity. This, however, puts it in line with two other exceptional, very metal-poor GCs - M 15 and NGC 4590. We also find a mild flattening of NGC 4372 in the direction of its rotation. Given its old age, this suggests that the flattening is indeed caused by the systemic rotation rather than tidal interactions with the Galaxy. Additionally, we estimate the dynamical mass of the GC M_dyn=2.0+/-0.5 x 10^5 M_Sun based on the dynamical model, which constrains the mass-to-light ratio of NGC 4372 between 1.4 and 2.3 M_Sun/L_Sun, representative of an old, purely stellar population.

arXiv commentAccepted for publication in A&A, 12 pages, 14 figures, 2 tables

References in corpus (36)

• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• A large stellar evolution database for population synthesis studies. I. Scaled solar models and isochrones
• Multiple populations in globular clusters. Lessons learned from the Milky Way globular clusters
• The ATLAS3D project - III. A census of the stellar angular momentum within the effective radius of early-type galaxies: unveiling the distribution of Fast and Slow Rotators
• Resolved Massive Star Clusters in the Milky Way and its Satellites: Brightness Profiles and a Catalogue of Fundamental Parameters
• Fast rotating massive stars and the origin of the abundance patterns in galactic globular clusters
• Formation and Dynamical Evolution of Multiple Stellar Generations in Globular Clusters
• A large stellar evolution database for population synthesis studies. II. Stellar models and isochrones for an alpha-enhanced metal distribution
• Homogeneous Photometry for Star Clusters and Resolved Galaxies. II. Photometric Standard Stars
• Detection of massive tidal tails around the globular cluster Pal 5 with SDSS commissioning data
• GaBoDS: The Garching-Bonn Deep Survey; IV. Methods for the Image reduction of multi-chip Cameras
• The dynamical distance and intrinsic structure of the globular cluster omega Centauri
• The properties of Galactic globular cluster sub-systems
• The second and third parameters of the Horizontal Branch in Globular Clusters
• The Bifurcated Age-Metallicity Relation of Milky Way Globular Clusters and its Implications For the Accretion History of the Galaxy
• Effects of Tidal Shocks on the Evolution of Globular Clusters
• Do globular clusters possess Dark Matter halos? A case study in NGC 2419
• No Energy Equipartition in Globular Clusters
• Homogeneous Photometry IV: On the Standard Sequence in the Globular Cluster NGC2419
• Peculiarities in Velocity Dispersion and Surface Density Profiles of Star Clusters
• Halo globular clusters observed with AAOmega: dark matter content, metallicity and tidal heating
• The velocity dispersion and mass-to-light ratio of the remote halo globular cluster NGC 2419
• Photometric catalog of nearby globular clusters (I)
• Globular Clusters with Dark Matter Halos. II. Evolution in Tidal Field
• N-body Models of Rotating Globular Clusters
• Space Velocities of Southern Globular Clusters. V. A Low Galactic Latitude Sample
• Luminosity and mass functions of the three main sequences of the globular cluster NGC 2808
• Rotation and multiple stellar population in globular clusters
• Testing Newtonian Gravity with AAOmega: Mass-to-Light Profiles of Four Globular Clusters
• A comparison between the stellar and dynamical masses of six globular clusters
• A dynamical study of Galactic globular clusters under different relaxation conditions
• 2D Fokker-Planck models of rotating clusters
• The ellipticities of Galactic and LMC globular clusters
• XMM-Newton observations of the Galactic globular clusters NGC 2808 and NGC 4372
• A calibration map for Wide Field Imager photometry

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• A stellar census in globular clusters with MUSE: The contribution of rotation to cluster dynamics studied with 200 000 stars
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• The internal rotation of globular clusters revealed by Gaia DR2
• The eye of Gaia on globular clusters kinematics: internal rotation
• Hubble Space Telescope Proper Motion (HSTPROMO) Catalogs of Galactic Globular Clusters. V. The rapid rotation of 47 Tuc traced and modeled in three dimensions
• Differences in the rotational properties of multiple stellar populations in M 13: a faster rotation for the "extreme" chemical subpopulation
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• The Gaia-ESO Survey: Kinematics of seven Galactic globular clusters
• The Search for Multiple Populations in Magellanic Cloud Clusters I: Two Stellar Populations in the Small Magellanic Cloud Globular Cluster NGC 121
• The strong rotation of M5 (NGC 5904) as seen from the MIKiS Survey of Galactic Globular Clusters
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• The orbital anisotropy profiles of nearby globular clusters from Gaia Data Release 2
• The Gaia-ESO Survey: Dynamical models of flattened, rotating globular clusters
• The ESO Multi-Instrument Kinematic Survey (MIKiS) of Galactic Globular Clusters: solid body rotation and anomalous velocity dispersion profile in NGC 5986
• Matching Globular Cluster Models to Observations
• The Gaia-ESO Survey: Detailed Abundances in the Metal-poor Globular Cluster NGC 4372
• Finding Black Holes with Black Boxes -- Using Machine Learning to Identify Globular Clusters with Black Hole Subsystems
• Understanding the central kinematics of globular clusters with simulated integrated-light IFU observations
• GalevNB: a conversion from N-BODY simulations to observations
• The Formation of Binary Star Clusters in the Milky Way and Large Magellanic Cloud
• G2C2-III: Structural parameters for Galactic globular clusters in SDSS passbands
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