Submillimeter View of Gas and Dust in the Forming Super Star Cluster in NGC 5253

TL;DR

This study uses submillimeter observations to analyze a giant molecular cloud surrounding a forming super star cluster in NGC 5253, revealing its properties, unusual gas-to-dust ratio, and implications for future star formation.

Contribution

It provides detailed characterization of Cloud D in NGC 5253, highlighting its low gas-to-dust ratio and the impact of cluster enrichment on cloud conditions, which is a novel insight.

Findings

Cloud D is hot and associated with the cluster but kinematically quiescent.

The gas-to-dust ratio is about 50, lower than expected for the galaxy.

Enrichment by the cluster may have stalled the cluster wind, affecting future star formation.

Abstract

A giant molecular cloud has been detected surrounding the supernebula in NGC 5253, revealing details of the formation and feedback process in a very massive star cluster. "Cloud D" was recently mapped in CO J=3-2 with the Submillimeter Array. The cloud surrounds a currently forming massive cluster of mass ~10$^6$ $\rm M_\odot$ and luminosity ~10$^9$ $\rm L_\odot$. Cloud D is hot, clearly associated with the cluster, yet kinematically relatively quiescent. The dust mass is ~15,000 $\rm M_\odot$, giving a gas-to-dust ratio of ~50, nearly an order of magnitude lower than expected for this low metallicity galaxy. We posit that enrichment by the cluster, leading to a stalled cluster wind, has created the unusual conditions in Cloud D. The absence of current mechanical impact of the young cluster on the cloud, in spite of the presence of thousands of O stars, may permit future generations of stars to form near the massive cluster.