Pairs of supermassive black holes in galaxies may be rarer than previously thought

22 September 2015 Astronomy Now

There may be fewer pairs of supermassive black holes orbiting each other at the cores of giant galaxies than previously thought, according to a new study. When two massive galaxies harbouring supermassive black holes collide, their black holes ultimately combine — a process that could be the strongest source of elusive gravitational waves, still yet to be directly detected.