Researchers have discovered emission from the secondary black hole in the binary system of blazar OJ 287 for the first time. This groundbreaking discovery was made by observing the polarization of light coming from OJ 287, which is located about 3.8 billion light-years from Earth.
OJ 287 is a type of active galactic nucleus (AGN) known as a blazar. Blazars are characterized by their bright, highly variable jets of material that are ejected from their central supermassive black holes. OJ 287 is unique among blazars in that it is known to be a binary system, with two supermassive black holes orbiting each other.
The primary black hole in OJ 287 is about 18 billion times more massive than the Sun, while the secondary black hole is about 150 times more massive than the Sun. The two black holes are separated by only about 10 microarcseconds, which is equivalent to the width of a human hair held at arm's length.
The researchers used seven telescopes in the U.S., Japan, and China to monitor the polarization of light coming from OJ 287 over a period of several years. They found that the polarization of light from OJ 287 varies over time, and that this variation can be explained by the presence of two separate signals, one from the primary black hole and the other from the secondary black hole.
The researchers say that this is the first time that they have been able to directly observe the secondary black hole in OJ 287. This discovery has important implications for our understanding of binary black hole systems and the evolution of galaxies.
Journal Information: Alok C. Gupta et al, Quasi-simultaneous Optical Flux and Polarization Variability of the Binary Super Massive Black Hole Blazar OJ 287 from 2015 to 2023: Detection of an Anticorrelation in Flux and Polarization Variability, The Astrophysical Journal Letters (2023). DOI: 10.3847/2041-8213/acfd2e