Chromosome Maps Of Young LMC Clusters: Coeval Multiple Populations.pdf

This study investigates the multiple populations (MPs) phenomenon in young star clusters within the Large Magellanic Cloud (LMC). The authors use new Hubble Space Telescope (HST) data to compare two LMC clusters, NGC 2121 and NGC 1783, with an intermediate-age cluster from the Small Magellanic Cloud, Lindsay 1, and a Galactic globular cluster.

Key Findings:

1. MPs Correlation with Cluster Age: The research demonstrates a clear correlation between the width of the red giant branch (RGB) in specific pseudo-colour images (CF275W, F343N, F438W) and the age of the clusters. Older clusters exhibit larger RGB widths.

2. Age Difference in NGC 2121: The HST data reveal that NGC 2121 has two populations with an age difference of approximately 6 ± 12 million years, suggesting a recent star formation episode.

3. He-abundance Variations in NGC 2121: The study explores helium enrichment within NGC 2121, placing constraints on any models attempting to explain the chemical anomalies in globular clusters.

4. Comparative Analysis: By comparing these clusters, the authors aim to understand how the MPs phenomenon evolves with cluster age and host galaxy environment.

Methodology:

- The study utilizes HST data for detailed photometric analysis.
- Chromosome maps are constructed using specific diagnostic tools to identify multiple populations.
- Age differences between subpopulations are estimated, providing insights into the formation and evolution of MPs.