On the evolution of structural parameters of old globular clusters in the Large Magellanic Cloud

TL;DR

This study analyzes the structural parameters of old globular clusters in the Large Magellanic Cloud, finding they lack extended stellar structures and exhibit different concentration properties compared to Galactic globular clusters, influenced by their environment.

Contribution

It provides the first detailed comparison of LMC globular clusters' structural parameters with those of Galactic clusters, highlighting environmental effects on their evolution.

Findings

LMC GCs do not show extended stellar structures like GGCs.

Concentration parameter c depends on internal dynamics and position.

LMC GCs have smaller c values and differ in structural ratios.

Abstract

We present result from DECam SDSS i PSF photometry of the radial stellar density profiles of the Large Magellanic Cloud (LMC) old globular clusters (GCs) NGC1841, 2210, Hodge11 and Reticulum, which extent out of ~ 380 pc from their centres. We found that the studied LMC GCs would not seem to exhibit extended stellar structures like those frequently seen in Galactic globular clusters (GGCs), which could suggest that the LMC gravitational field has not been efficient in stripping stars off its GCs. The concentration parameter $c$ of the studied LMC GCs would seem to depend on both the internal dynamics and the position of the GC in the galaxy, as the Jacobi-to-cluster radius ratio does. When comparing them with GGCs with similar masses and age-to-half-mass relaxation times ratios, the studied LMC GCs would seem to have the smallest concentration parameter $c$ values and step aside of the GGC relationship in the core-to-half-light radius ratio ($r_c/r_h$) vs half-light-to-tidal radius ratio ($r_h/r_t$) plane. These observational differences could suggest that other conditions, like the gravitational potential of the host galaxy and/or the orbital parameters (e.g. halo- or disc- like orbits), could play some role in the evolution of the structural parameters of these two GC populations.