An artist’s impression of a supermassive black hole surrounded by a vast disc of gas and dust. Astronomers say smaller black holes merging in the disc could produce visible light, providing a new tool for studying such collisions. Image: NASA/JPL-Caltech
The Milky Way, like most if not all large galaxies, features a supermassive black hole at its core. Astronomers believe smaller black holes also congregate near the core where it might be possible to detect mergers by their interactions with gas swirling around the much more massive supermassive black hole.
Such mergers are currently detected by the gravitational waves they generate, so-called “ripples” in the fabric of spacetime. They do not, by definition, produce a light signature that would help astronomers pinpoint their locations and glean additional details.
But a new study in The Astrophysical Journal Letters offers a possible way to detect such mergers by the effects they might have on gas surrounding a supermassive black hole.
A large amount of gas falling onto the central black hole would generate a bright disk that would envelop any smaller black holes in the vicinity. Black hole pairs would interact with the gas and spiral closer to the central supermassive black ...