An international team of astronomers has obtained the first direct visual confirmation that a binary black hole exists, the website infohub.kz reports. The study was carried out by a group led by Silke Britzen of the Max Planck Institute for Radio Astronomy (MPIfR) in Bonn: the scientists found observational evidence of a pair of supermassive black holes at the center of the galaxy Mrk 501. The results have been accepted for publication in the journal Monthly Notices of the Royal Astronomical Society.
The work was based on radio data collected at multiple frequencies over 23 years of observations. In addition to the bright jet directed toward Earth, the astronomers were able to detect and track the movement of a second jet pointing in the opposite direction. This jet sweeps counterclockwise around the main black hole. In addition, in June 2022 the researchers recorded a gravitational lensing effect in the form of an Einstein ring: light from the second jet was bent by the gravity of the first black hole.
According to the scientists' calculations, the objects, with masses ranging from 100 million to a billion solar masses, orbit each other in roughly 121 days at a distance of just 250–540 astronomical units. Depending on their exact masses, they could collide and merge in as little as 100 years. Because of the enormous distance, current telescopes cannot visually resolve the pair, but the system is to be studied using pulsar timing arrays (PTAs), which can detect low-frequency gravitational waves. Co-author Hector Olivares also took part in the study.