The role of mergers in producing galaxies, together with the finding that most large galaxies harbour black holes in their nuclei, implies that binary supermassive black hole systems should be common. This study reports that the quasar SDSS J153636.22+044127.0 is a candidate binary, and shows two broad-line emission systems, separated in velocity by 3,500 km s−1.
- Todd A. Boroson
- Tod R. Lauer
