Wait: Do black holes *really* swarm in the core of globular cluster NGC 6397?

Recently here on the blog I wrote about the globular cluster NGC 6397, a collection of a hundreds of thousands of stars in a compact ball, orbiting the Milky Way and currently about 8,000 light years from Earth.

I wrote about it because a pair of astronomers ran statistical models on the way the stars are orbiting in the cluster, and claimed there's a pretty good chance that there's a swarm of stellar-mass black holes in the cluster core, with a total mass of 1,000–2,000 times the Sun's, meanin...