Astronomers have confirmed the presence of a second supermassive black hole in the turbulent heart of a distant galaxy.
These flares arise as the diving black hole heats the disk of material and causes it to"burp" out hot gas as expanding bubbles.
Around four decades ago, Aimo Sillanpää, an astronomer at the University of Turku in Finland and co-author of the new research, and his colleagues noticed a prominent pattern in the emission of OJ 287. They identified two cycles — one of about 12 years and one of about 55 years. This indicated two black holes swirling around each other, with the shorter cycle being the orbital period and the longer cycle arising from the orientation of this orbit shifting over time.
During an observational campaign in 2021/2022 conducted by a number of telescopes, astronomers were finally able to obtain direct evidence of the secondary black hole diving through the accretion disk and gather signals from that second cosmic titan.