A Hidden Population of High-Redshift Double Quasars Unveiled by Astrometry
"If you thought that the Nobel-Prize-winning LIGO discovery of stellar mass black hole mergers was cool, just think about the possibility of merging black holes with masses millions or billions of times that of the Sun! The enormous masses of black holes in centers of galaxies almost defy imagination. One would think that such energetic merger events or their progenitors -- supermassive black holes orbiting one another on tight orbits -- would be easy to identify. Yet they have so far eluded researchers, and discovering such objects remains a tantalizing goal of modern observational astronomy."
Read more at Nature Astronomy.