On the structure of Small Magellanic Cloud star clusters

Abstract

It has been recently shown from observational data sets the variation of structural parameters and internal dynamical evolution of star clusters in the Milky Way and in the Large Magellanic Cloud (LMC), caused by the different gravitational field strengths that they experience. We report here some hints for such a differential tidal effects in structural parameters of star clusters in the Small Magellanic Cloud (SMC), which is nearly 10 times less massive than the LMC. A key contribution to this study is the consideration of the SMC as a triaxial spheroid, from which we estimate the deprojected distances to the SMC center of the statistically significant sample of star clusters analyzed. By adopting a 3D geometry of the SMC, we avoid the spurious effects caused by considering that a star cluster observed along the line-of-sight is close to the galaxy center. When inspecting the relationships between the star cluster sizes (represented by the 90% light radii), their eccentricities, masses and ages with the deprojected distances, we find: (i) the star cluster sizes are not visibly affected by tidal effects, because relatively small and large objects are spread through the SMC body. (ii) Star clusters with large eccentricities (> 0.4) are preferentially found located at deprojected distances smaller than $\sim$ 7-8 kpc, although many star clusters with smaller eccentricities are also found occupying a similar volume. (iii) Star clusters more massive than log(M /Mo) $\sim$ 4.0 are among the oldest star clusters, generally placed in the outermost SMC region and with a relative small level of flattening. These findings contrast with the more elongated, generally younger, less massive and innermost star clusters.

arXiv comment6 pages, 6 figures. Accepted por publication in Astronomy & Astrophysics

References in corpus (41)

• Dark Matter Substructure in Galactic Halos
• Dynamical evolution of star clusters in tidal fields
• The Magellanic Clouds Photometric Survey: The Small Magellanic Cloud Stellar Catalog and Extinction Map
• The VMC Survey - I. Strategy and First Data
• An analytical description of the disruption of star clusters in tidal fields with an application to Galactic open clusters
• A New Look at the Kinematics of Neutral Hydrogen in the Small Magellanic Cloud
• Star cluster disruption by giant molecular clouds
• Third-Epoch Magellanic Cloud Proper Motions II: The Large Magellanic Cloud Rotation Field in Three Dimensions
• Age Determination of Six Intermediate-age SMC Star Clusters with HST/ACS
• A distance determination to the Small Magellanic Cloud with an accuracy of better than 2 percent based on late-type eclipsing binary stars
• Effects of Tidal Shocks on the Evolution of Globular Clusters
• Small Dwarf Galaxies Within Larger Dwarfs: Why Some Are Luminous While Most Go Dark
• The Orbital Histories of Magellanic Satellites Using Gaia DR2 Proper Motions
• The life cycle of star cluster in a tidal field
• Modeling the formation and evolution of star cluster populations in galaxy simulations
• Lifetimes of tidally limited star clusters with different radii
• SMASH - Survey of the MAgellanic Stellar History
• Clusters in the solar neighbourhood: how are they destroyed?
• The Line-of-Sight Depth of Populous Clusters in the Small Magellanic Cloud
• The VMC Survey. XXV. The 3D structure of the Small Magellanic Cloud from Classical Cepheids
• The age-metallicity relationship of the Large Magellanic Cloud field star population from wide-field Washington photometry
• On the Interpretation of the Age Distribution of Star Clusters in the Small Magellanic Cloud
• The VMC survey - XXVI. Structure of the Small Magellanic Cloud from RR Lyrae stars
• The mass of the Milky Way out to 100 kpc using halo stars
• Dissolution is the solution: on the reduced mass-to-light ratios of Galactic globular clusters
• Study of open clusters within 1.8 kpc and understanding the Galactic structure
• If it does not kill them, it makes them stronger: collisional evolution of star clusters with tidal shocks
• The Influence of Orbital Eccentricity on Tidal Radii of Star Clusters
• An Updated SMC and Magellanic Bridge Catalog of Star Clusters, Associations and Related Objects
• The VISCACHA survey - I. Overview and First Results
• The Star Clusters of the Small Magellanic Cloud: Structural Parameters
• SMC west halo: a slice of the galaxy that is being tidally stripped? Star clusters trace age and metallicity gradients
• Characteristic radii of the Milky Way Globular Clusters
• The Effects of Orbital Inclination on the Scale Size and Evolution of Tidally Filling Star Clusters
• The long-term evolution of star clusters formed with a centrally-peaked star-formation-efficiency profile
• Mass distribution and structural parameters of Small Magellanic Cloud star clusters
• Evidence of differential tidal effects in the old globular cluster population of the Large Magellanic Cloud
• N-body Models of Extended Clusters
• The inefficiency of satellite accretion in forming extended star clusters
• Formation imprints in the kinematics of the Milky Way globular cluster system
• On a possible origin for the lack of old star clusters in the Small Magellanic Cloud

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• STEP Survey II: Structural Analysis of 170 star clusters in the SMC
• The kinematics of Small Magellanic Cloud star clusters
• Star cluster formation from giant molecular clouds in the Small Magellanic Cloud about 2 Gyr ago: their origin, structures, and kinematics
• The spatial distributions of blue main-sequence stars in Magellanic Cloud star clusters
• Residual velocities of Small Magellanic Cloud star clusters
• Revisiting a detached stellar structure in the outer northeastern region of the Small Magellanic Cloud