Evidence for a recoiling black hole has been found using data from the Chandra X-ray Observatory, XMM-Newton, the Hubble Space Telescope (HST), and several ground-based telescopes. A new paper reports that this black hole kickback was caused either by a slingshot effect produced in a triple black hole system, or from the effects of gravitational waves produced after two supermassive black holes merged a few million years earlier.
triple black hole system