James Webb telescope solves cosmic murder mystery in 'Pablo's Galaxy' — and it was a black hole who done it

New observations of a strange galaxy show it was slowly starved to death by its own black hole.

Two telescopes peered deep into space at the galaxy GS-10578, nicknamed "Pablo's Galaxy," after the name of the astronomer who previously studied it. The galaxy is large for its age: roughly 200 billion times the mass of the sun, with most of its stars lighting up between 11.5 billion years and 12.5 billion years ago. (For reference, the universe is roughly 13.8 billion years old.)

To scientists' surprise, they learned a supermassive black hole embedded in the galaxy slowly removed the cold gas needed for stars to grow, instead of (as models predict) tearing the galaxy apart.

"Pablo’s Galaxy appears to have 'lived fast and died young'," researchers wrote about the new work, published in Nature Astronomy on Monday, in a University of Cambridge statement. "It stopped forming new stars, despite its relatively young age, due to an almost total absence of the cold gas stars need to form."

The research team described the death as happening "by a thousand cuts," because the black hole heated up gas moving through the galaxy. This meant any cold gas was choked off from resupplying the galaxy, making it more difficult for stars to form.

"There was essentially no cold gas left. It points to a slow starvation, rather than a single dramatic death blow," lead author Jan Scholtz, from Cambridge's Cavendish Laboratory and the Kavli Institute for Cosmology, said in the statement.

The results came by analyzing data from both the James Webb Space Telescope, as well as the Atacama Large Millimeter Array (ALMA). ALMA revealed no traces of carbon monoxide, which is an indicator of cold, star-forming hydrogen gas, in the galaxy. JWST, meanwhile, showed the supermassive black hole shooting out neutral gas at 400 kilometers per second (nearly 900 mph). At such rates, the galaxy would have run out of star fuel in only 16 million to 220 million years, a fraction of the typical billions of years for stars to die out.

Pablo's Galaxy appears to be representative of galaxies from the young universe that appear to be aging faster than expected. "Before Webb, these were unheard of," Scholtz said. "Now we know they're more common than we thought – and this starvation effect may be why they live fast and die young."