A landmark discovery from the universe's infancy
An international team led by researchers at Leiden University has detected a substantial amount of cold molecular gas in the massive, star‑forming galaxy REBELS‑25. The finding offers fresh insight into how young galaxies assembled their stellar mass during the first few billion years after the Big Bang.
Observations and methodology
REBELS‑25 is observed at a time when the cosmos was only about 5 % of its current age – roughly 700 million years after the Big Bang. Using millimeter‑wave interferometry, the scientists traced carbon‑monoxide (CO) emission, a reliable proxy for cold, dense molecular gas. The inferred gas mass far exceeds previous estimates for galaxies of similar size and epoch.
Implications for galaxy evolution
Cold molecular gas serves as the immediate raw material for star formation. Detecting such a large reservoir at this early stage suggests that the star‑formation rate in REBELS‑25 and comparable systems may have been significantly higher than earlier models predicted. This could help explain why some of the earliest known galaxies already host massive stellar populations.
Publication and future work
The study appears in the journal "Monthly Notices of the Royal Astronomical Society". The team plans follow‑up high‑resolution observations to map the gas distribution within the galaxy and to explore potential interactions with the surrounding intergalactic medium.