An optically-dark merging system at z~6 detected by JWST

Understand

Near- to mid-Infrared observations (from Spitzer and JWST) have revealed a hidden population of galaxies at redshift z=3-6, called optically-dark objects, which are believed to be massive and dusty star-formers.

• While optically-dark sources are widely recognized as a significant component of the stellar mass function, the history of their stellar mass assembly remains unexplored.
• However, they are thought to be the progenitors of the more massive early-type galaxies found in present-day groups and clusters.
• It is thus important to examine the possible connection between dark sources and merging events, in order to understand the environment in which they live.