Structures in surface-brightness profiles of LMC and SMC star clusters: evidence of mergers?

TL;DR

This study analyzes surface-brightness profiles of LMC and SMC star clusters, identifying structural features and deviations that suggest possible cluster mergers, with implications for understanding cluster evolution.

Contribution

It provides detailed structural analysis of Magellanic Cloud clusters, highlighting deviations from models as potential merger indicators, including first-time observations and profile fitting.

Findings

Double profiles in three binary clusters.

Deviations from EFF profiles in some clusters.

Extended profiles in blue clusters.

Abstract

The LMC and SMC are rich in binary star clusters, and some mergers are expected. It is important to characterize single clusters, binary clusters and candidates to mergers. We selected a sample of star clusters in each Cloud with this aim. Surface photometry of 25 SMC and 22 LMC star clusters was carried with the ESO Danish 1.54 m telescope. 23 clusters were observed for the first time for these purposes. We fitted Elson, Fall and Freeman (1987, EFF) profiles to the data, deriving structural parameters, luminosities and masses. We also use isophotal maps to constrain candidates to cluster interactions.} {The structural parameters, luminosities and masses presented good agreement with those in the literature. Three binary clusters in the sample have a double profile. Four clusters (NGC 376, K 50, K 54 and NGC 1810) do not have companions and present as well important deviations from EFF profiles. The present sample contains blue and red Magellanic clusters. Extended EFF profiles were detected in some blue clusters. We find evidence that important deviations from the body of EFF profiles might be used as a tool to detect cluster mergers.