Shadows of a supermassive black hole binary system uncovers new method for studying them

Astronomers have developed a technique that could measure the ‘shadows’ of black hole binary systems in distant galaxies.

In this simulation of a supermassive black hole merger, the blue-shifted black hole closest to the viewer amplifies the red-shifted black hole in the back through gravitational lensing. The researchers discovered a distinct dip in brightness when the closest black hole passed in front of the shadow of its counterpart, an observation that could be used to measure the size of both black holes and test alternative theories of gravity. Credit: Jordy Davelaar