On the hunt for ‘hierarchical’ black holes
Black holes, detected by their gravitational wave signal as they collide with other black holes, could be the product of much earlier parent collisions. Such an event has only been hinted at so far, but scientists at the University of Birmingham in the U.K., and Northwestern University in the U.S., believe we are getting close to tracking down the first of these so-called “hierarchical” black holes.
phys.org
Go to Source