# Black Holes at Galaxy Hearts May Spark Star Birth, New Maps Reveal
At the luminous cores of some galaxies, supermassive black holes devour matter and blast out powerful jets, creating regions so bright they outshine all the stars in their host galaxies combined. For years, astronomers expected these extreme environments to suppress star formation by heating the surrounding gas. But new observations suggest the opposite: these cosmic furnaces may actually ignite new stars.
A research team used the Very Large Telescope in Chile and the orbiting Chandra X-Ray Observatory to map nine bright galactic cores—called active galactic nuclei—in galaxies near the Milky Way. The high-resolution instruments allowed the scientists to examine these regions in unprecedented detail. They then built theoretical models to predict black hole behavior and compared those predictions against their observations.
The team identified a consistent pattern across all nine galaxies. Each contained areas of star formation shaped like rings or arcs, positioned between 2,600 and 19,600 light-years from the galactic centers. "That is a very surprising finding to me, and also, I think, to our community," said Peixin Zhu, an astrophysicist at the Center for Astrophysics, Harvard and Smithsonian and the study's lead author. The findings were published in the Astrophysical Journal.
Star formation requires temperatures barely above absolute zero. Because supermassive black holes eject jets and waves that heat surrounding gas, astronomers had long assumed these active regions would prevent star birth. Black holes pull in material through their immense gravity, a process called accretion. "Due to their immense gravity, black holes are known for accreting, or pulling in, material," Zhu explained. That process could be thought to "take over all the gas" that might otherwise help form stars. "But then the fact is that in addition to accreting all those things, they also eject things."
The momentum and energy from that ejected material could ultimately promote star formation, though the exact mechanics remain unclear and will require future research.
The team also mapped the structure of charged gas emanating from the black holes. This radiation doesn't spread evenly in all directions. Instead, it forms a bicone—a shape resembling two ice cream cones aimed away from each other, with their points touching at the black hole. Meanwhile, fast shockwaves launched from the black holes extended perpendicular to these bicones across all nine galaxies.
That specific geometry came as a second surprise. When Zhu initially saw it in her results, she felt skeptical. She ran simulations of black hole dynamics, and to her surprise, they aligned with the observations. "They actually did predict a shockwave going perpendicular to AGN winds or jets," she said, "and that's the point I feel like, okay, I'm not seeing something nonsense."
Niel Brandt, an astrophysicist at Penn State who was not involved with the research, agreed the perpendicular angle was unexpected. "What is the cause of that? That's what I find to be a little puzzling still," he said. "This is something that's a little mysterious."
Active galactic nuclei "are extreme physics laboratories," Brandt noted. They contain high-temperature plasma surrounding regions where powerful gravity operates. Supermassive black holes "are thought to play a role in cosmic evolution," he added. "We think they have something to do with how galaxies put themselves together. We've suspected this for a long time."
The research offers a structural roadmap that might apply broadly to active galactic nuclei: a ring or arc of star formation, bicones of radiation, and perpendicular shocks. This framework brings order to what had seemed chaotic. "You kind of look at this and you just think, well, this is just a confusing mixture. It's just a mess. Maybe we're not going to be able to sort it out," Brandt said. "But they're arguing that maybe you can sort it out. … They are arguing that there is some method to the madness."
Study co-author Lisa Kewley, director of the Center for Astrophysics, Harvard and Smithsonian, said in a statement: "We're seeing that black holes are not just consuming material at the centers of galaxies, but they're actively reshaping their surroundings."
With just nine galaxies, the team cannot draw conclusions about the entire universe. But Zhu said they hope to expand that sample with future work. Telescopes such as the Extremely Large Telescope and the Giant Magellan Telescope, both under construction in Chile, are expected to view the cosmos with extremely high resolution.
**Sources:**
Smithsonian Magazine: https://www.smithsonianmag.com/smithsonian-institution/active-supermassive-black-holes-may-be-engines-of-star-formation-not-just-destruction-study-suggests-180989517/