Supermassive black hole stunts star growth in other galaxies

• Active supermassive black holes can stunt star growth even far outside their home galaxies. That’s according to a new study from researchers at the University of Arizona.
• When these active supermassive black holes are spewing intense radiation, we call them quasars. We’ve long known quasars can shape the evolution of their home galaxies. But the new research shows they affect distant galaxies as well.
• Researchers observed weaker signatures of star formation in galaxies nearby quasars. This suggests galaxies don’t evolve in isolation but as part of an interconnected galactic ecosystem.

You deserve a daily dose of good news. For the latest in science and the night sky, click here to subscribe to our free daily newsletter.

The University of Arizona published this original article on February 18, 2026. Edits by EarthSky.

Supermassive black hole stunts star growth in other galaxies

Astronomers think black holes reside at the center of most, if not all, galaxies. And on February 16, 2026, the University of Arizona said the intense radiation they emit can slow star growth. Not just in their host galaxy, but also in galaxies millions of light-years away. The University of Arizona’s Yongda Zhu led the study, which found weaker signatures of star formation in nearby galaxies. Zhu said:

Traditionally, people have thought that because galaxies are so far apart, they evolve largely on their own. But we found that a very active, supermassive black hole in one galaxy can affect other galaxies across millions of light-years, suggesting that galaxy evolution may be more of a group effort.

Zhu calls this idea the galaxy ecosystem and compares it to the intertwined ecological systems on Earth. Zhu said:

An active supermassive black hole is like a hungry predator dominating the ecosystem. Simply put, it swallows up matter and influences how stars in nearby galaxies grow.

The researchers published their peer-reviewed study in The Astrophysical Journal Letters on December 3, 2025.

Supermassive black holes

Since they were first predicted in the early 1900s, the destructive and ominous nature of black holes has fascinated not only scientists, but the public as well. Considered the most extreme objects found in the universe, black holes contain immense mass and gravity, capable of capturing nearby matter and even light if it ventures too close. A small subset, including the Milky Way‘s central black hole, are known as supermassive. These boast masses millions and sometimes even billions of times that of our sun.

As their name implies, black holes per se are invisible. However, when supermassive black holes actively devour surrounding matter, they can appear as extremely bright specks in telescope images, sometimes emitting hundreds of trillions of times more energy than the sun. Astronomers refer to these cosmic monsters as quasars. It’s a phase in a black hole’s life when gas and dust form a swirling disk that releases enormous energy as it spirals inward. Quasars often outshine the entire host galaxy.

Resolving a mystery

Early observations from the James Webb Space Telescope appeared to show fewer galaxies surrounding enormous quasars during the universe’s infancy. This result was surprising. That’s because large galaxies are commonly found in dense clusters, rather than isolation. Zhu said:

We were puzzled … Then we realized the galaxies might actually be there, but difficult to detect because their very recent star formation was suppressed.

That realization led to a bold new idea: Could these very bright, supermassive black holes affect not only their own galaxies but also stifle star formation in neighboring galaxies?

To test this idea, the team studied one of the most luminous quasars ever observed: J0100+2802. This quasar is powered by a supermassive black hole roughly 12 billion times the mass of the sun. Light from this quasar allows astronomers to see the universe when it had not yet even reached its 1-billion-year birthday.

Measuring O III: ionized oxygen

The team of scientists used Webb to measure emissions of a specific gas called O III, an ionized version of oxygen that traces very recent star formation in galaxies. A lower ratio of O III alludes to the disruption of ideal star-forming conditions in large clouds of cold gas. The team observed a clear distinction between galaxies within a million-light-year radius of the overpowering quasar: they showed weaker O III emission relative to their ultraviolet light, consistent with repressed, very recent star formation. Zhu said:

Black holes are known to ‘eat’ a lot of stuff. But during the active eating process and in their luminous quasar form, they also emit very strong radiation. The intense heat and radiation split the molecular hydrogen that makes up vast, interstellar gas clouds, quenching its potential to accumulate and turn into new stars.

Stars require very specific conditions to form, including large reservoirs of cold molecular hydrogen. This acts as the raw fuel for star formation. Scientists already knew that quasars, often located at the centers of young, rapidly growing galaxies, can destroy this gas within their own host galaxies, shutting down local star formation. What remained unclear, however, was whether this destructive influence extended beyond a quasar’s home galaxy. By using Webb to observe light from a quasar that existed more than 13 billion years ago, the team found evidence of suppressed star growth on a much larger scale. Zhu said:

For the first time, we have evidence that this radiation impacts the universe on an intergalactic scale. Quasars don’t just suppress stars in their host galaxies, but also in nearby galaxies within a radius of at least a million light-years.

The power of Webb

This discovery would have been impossible with any other telescope, according to Zhu.

This is because by the time light from objects as distant as quasar J0100+2802 reaches Earth, the expansion of the universe has stretched its wavelengths far into the infrared. Previous telescopes could not clearly detect these faint infrared signals, making Webb uniquely capable of observing early-universe phenomena.

Our galaxy, the Milky Way, likely once had its own quasar. It is not active today, but the researchers wonder how this quasar impacted the formation of our own galaxy, as well as the other galaxies in its local environment.

The team hopes to test whether the phenomenon is widespread across multiple quasar fields. And they’d like to better understand exactly how galaxies are affected by neighboring quasars. They’re also curious to know whether other, less obvious factors are at play. Zhu said:

Understanding how galaxies influenced one another in the early universe helps us better understand how our own galaxy came to be. Now we realize that supermassive black holes may have played a much larger role in galaxy evolution than we once thought … acting as cosmic predators, influencing the growth of stars in nearby galaxies during the early universe.

Bottom line: A new study shows that supermassive black holes at the centers of galaxies can slow star growth even in other galaxies that are millions of light-years away.

Source: Quasar Radiative Feedback May Suppress Galaxy Growth on Intergalactic Scales at z = 6.3

Via University of Arizona

The post Supermassive black hole stunts star growth in other galaxies first appeared on EarthSky.