Exploring the nature and synchronicity of early cluster formation in the Large Magellanic Cloud: III. Horizontal Branch Morphology

TL;DR

This study uses high-quality Hubble data to analyze horizontal branch morphology in LMC globular clusters, revealing similarities with outer Galactic halo clusters and a correlation with age.

Contribution

It provides new, precise photometric analysis of LMC clusters, showing their horizontal branch morphology is similar across the system and comparable to outer halo Galactic clusters.

Findings

LMC clusters have similar HB morphology regardless of location.

LMC clusters are slightly redder than inner halo Galactic clusters.

HB morphology correlates with cluster age.

Abstract

We leverage new high-quality data from Hubble Space Telescope program GO-14164 to explore the variation in horizontal branch morphology among globular clusters in the Large Magellanic Cloud (LMC). Our new observations lead to photometry with a precision commensurate with that available for the Galactic globular cluster population. Our analysis indicates that, once metallicity is accounted for, clusters in the LMC largely share similar horizontal branch morphologies regardless of their location within the system. Furthermore, the LMC clusters possess, on average, slightly redder morphologies than most of the inner halo Galactic population; we find, instead, that their characteristics tend to be more similar to those exhibited by clusters in the outer Galactic halo. Our results are consistent with previous studies showing a correlation between horizontal branch morphology and age.