Echo mapping hints dark matter clusters around supermassive black holes

Astronomers used reverberation (echo) mapping to probe gas around supermassive black holes in 14 galaxies, finding in five cases that the enclosed mass increases with distance from the SMBH beyond what visible matter can explain. The results hint at dark matter clustering around SMBHs like Sagittarius A* and M87, offering a new method to study dark matter environments, though the findings are preliminary and not conclusive.