Supermassive black hole blows galactic gas at 2,235,600 mph; cuts off star power

Astronomers, using the NASA/ESA James Webb Space Telescope, have confirmed that supermassive black holes can deprive their host galaxies of the gas required for star formation.

An international team, co-led by the University of Cambridge, observed a galaxy similar in size to the Milky Way from about two billion years after the Big Bang. Like many large galaxies, this one has a supermassive black hole at its center. However, the galaxy is nearly “dead,” having largely ceased the formation of new stars.

“Based on earlier observations, we knew this galaxy was in a quenched state: it’s not forming many stars given its size, and we expect there is a link between the black hole and the end of star formation,” said co-lead author Dr Francesco D’Eugenio from Cambridge’s Kavli Institute for Cosmology.

“However, until Webb, we haven’t been able to study this galaxy in enough detail to confirm that link, and we haven’t known whether this quenched state is temporary or permanent.”

Webb discovers cold, dense gas

The galaxy, officially named GS-10578 but nicknamed ‘Pablo’s Galaxy’ after the researcher who chose to study it closely, is unusually massive for such an early stage in the universe’s history. It has a mass about 200 billion times that of the Sun, with most of its stars having formed between 12.5 and 11.5 billion years ago.

“In the early universe, most galaxies are forming lots of stars, so it’s interesting to see such a massive dead galaxy at this period in time,” explained co-author Professor Roberto Maiolino from the Kavli Institute for Cosmology. He noted that since the galaxy reached this massive size, the process that halted star formation likely occurred quite rapidly.

Using the James Webb Space Telescope, researchers discovered that Pablo’s Galaxy is expelling vast amounts of gas at approximately 621 miles per second (1,000 kilometers per second), fast enough to escape the galaxy’s gravitational hold. These 2,235,600 miles per hour winds, driven by the supermassive black hole, are pushing gas out of the galaxy.

While similar galaxies with active black holes also have outflows of hot gas, the expelled gas in Pablo’s Galaxy is unique. Webb detected a new component: colder, denser gas that emits no light, making it invisible to previous telescopes .

However, Webb’s advanced sensitivity allowed the team to observe these dark gas clouds by detecting how they block some of the light from the galaxy behind them.

Pablo’s Galaxy: Killed by its own black hole?

The mass of gas being expelled from Pablo’s Galaxy is greater than the amount needed for continued star formation, effectively starving the galaxy. “We found the culprit,” said D’Eugenio in the press release . “The black hole is killing this galaxy and keeping it dormant, by cutting off the source of ‘food’ the galaxy needs to form new stars.”

While theoretical models had long suggested that black holes could halt star formation in galaxies, the James Webb Space Telescope provided the first direct evidence of this phenomenon. Earlier models also predicted that such star formation shutdowns would disrupt galaxies, destroying their structure.

However, the stars in this galaxy remain in orderly motion, indicating that black hole-driven quenching may not always cause such chaos.

Further observations with the Atacama Large Millimeter-Submillimeter Array (ALMA) will examine the coldest, darkest gas in the galaxy to determine if any remaining fuel for star formation is hidden and to assess the broader influence of the supermassive black hole on the surrounding region.

The study has been published in the journal Nature Astronomy .