# Searching for GC-like abundance patterns in young massive clusters II. - Results from the Antennae galaxies

## TL;DR

This study investigates the presence of multiple populations with light element variations in young massive clusters in the Antennae galaxies, finding no significant Al variations and discussing implications for the development of multiple populations.

## Contribution

First analysis of Al abundance variations in young (7-40 Myr) massive clusters, providing insights into the age at which multiple populations develop.

## Key findings

- No significant Al variations detected in studied clusters
- Small Al spreads observed, suggesting absence of MPs at young ages
- Implications for the evolution of multiple populations in star clusters

## Abstract

The presence of multiple populations (MPs) with distinctive light element abundances is a widespread phenomenon in clusters older than 6 Gyr. Clusters with masses, luminosities, and sizes comparable to those of ancient globulars are still forming today. Nonetheless, the presence of light element variations has been poorly investigated in such young systems, even if the knowledge of the age at which this phenomenon develops is crucial for theoretical models on MPs. We use J-band integrated spectra of three young (7-40 Myr) clusters in NGC 4038 to look for Al variations indicative of MPs. Assuming that the large majority (>70%) of stars are characterised by high Al content - as observed in Galactic clusters with comparable mass; we find that none of the studied clusters show significant Al variations. Small Al spreads have been measured in all the six young clusters observed in the near-infrared. While it is unlikely that young clusters only show low Al whereas old ones display different levels of Al variations; this suggests the possibility that MPs are not present at such young ages at least among the high-mass stellar component. Alternatively, the fraction of stars with field-like chemistry could be extremely large, mimicking low Al abundances in the integrated spectrum. Finally, since the near-infrared stellar continuum of young clusters is almost entirely due to luminous red supergiants, we can also speculate that MPs only manifest themselves in low mass stars due to some evolutionary mechanism.