Webb Reveals Slow Black-Hole Starvation Quenching Pablo’s Galaxy

Astronomers using the James Webb Space Telescope and ALMA traced Pablo’s Galaxy (GS-10578) back to about 11 billion years ago and found it ceased forming stars not due to a violent merger but through slow starvation by its central supermassive black hole. Repeated gas outflows expelled star-forming gas and prevented fresh cold gas from refilling the reservoir, leaving the galaxy—seen as a calm rotating disc—without fuel for new stars and ending star formation around 400 million years ago. With an estimated gas-loss rate of ~60 solar masses per year, the remaining fuel could have run out in roughly 16–220 million years, suggesting black-hole feedback as a key quenching mechanism in early galaxies and potentially explaining why some young galaxies look mature in the early universe.