Constraining globular cluster formation through studies of young massive clusters - III. A lack of gas and dust in massive stellar clusters in the LMC and SMC

TL;DR

This study searches for gas and dust in young massive clusters in the LMC and SMC to test models of multiple star formation episodes, but finds no such gas reservoirs, challenging current theoretical predictions.

Contribution

It provides observational evidence of a lack of gas and dust in young massive clusters, contradicting models that predict significant gas retention in such clusters.

Findings

No gas or dust detected in the surveyed clusters.

Gas observed near some clusters is unrelated to the clusters themselves.

Results challenge existing models of multiple star formation episodes in clusters.

Abstract

Scenarios that invoke multiple episodes of star formation within young globular clusters (GCs) to explain the observed chemical and photometric anomalies in GCs, require that clusters can retain the stellar ejecta of the stars within them and accrete large amounts of gas from their surroundings. Hence, it should be possible to find young massive clusters in the local Universe that contain significant amounts ($>10$\%) of the cluster mass of gas and/or dust within them. Recent theoretical studies have suggested that clusters in the Large Magellanic Cloud (LMC) with masses in excess of $10^4$\msun\, and ages between $30$ and $\sim300$~Myr, should contain such gas reservoirs. We have searched for \hi\ gas within 12 LMC (and 1 SMC) clusters and also for dust using {\em Spitzer} 70\micron\ and 160\micron\ images. No clusters were found to contain gas and/or dust. While two of the clusters have \hi\ at the same (projected) position and velocity, the gas does not appear to be centred on the clusters, but rather part of nearby clouds or filaments, suggesting that the gas and cluster are not directly related. This lack of gas ($<1$\% of the stellar mass) is in strong tension with model predictions, and may be due to higher stellar feedback than has been previously assumed or due to the assumptions used in the previous calculations.