A team of astronomers at the Space Telescope Science Institute, working with one colleague from the University of St Andrews' Center for Exoplanet Science and another from the European Southern Observatory, has confirmed the existence of a lone black hole. In their paper published in The Astrophysical Journal, the group describes how they studied newer data regarding an object they had spotted several years ago to confirm its identity.
Reads over actual paper
I’m going to take your word for it.
Given how difficult that seems to be to find that kind of visual disturbance in a place like the galactic center where things are moving relatively fast, no way is a lone black hole going to be seen anywhere outside that kind of bee swarm of stars. But there certainly must be a lot of them, no reason to think there aren’t.