Astronomers have pinpointed the black hole at the heart of galaxy M77, which is hiding in a disc of dust. The discovery will help astronomers to learn about the different types of active galactic nucleus (AGN), where a galaxy’s central black hole is surrounded by superheated gas.
There are many kinds of AGN (some burst, some are bright, others are more subdued), but one theory suggests that they are all fundamentally the same; it’s the angle at which we view the dust disc around them that makes them appear different. It was uncertain whether a disc of dust could obscure a black hole enough to cause the changes seen, however.
By observing the temperature profile of the disc in M77, the astronomers were able to map its shape and position the black hole, both of which greatly support this theory. “Our results… could help our understanding of the history of the Milky Way, which harbours a supermassive black hole at its centre that may have been active in the past,” says Gámez Rosas from the Max Planck Institute, who led the study. www.mpia.de