At www.space.com/40196-black-hole-swarm-milky-way-heart.html … a swarm of thousands of black holes MAY surround the giant black hole believed to be at the heart of our galaxy, according to a new study. At the centre of the Milky Way lies Sagitarrius A (thought to be a 'massive' black hole). Cosmologists think black holes grow by engulfing smaller black holes – and the search has been on for them. Funnily enought, the Chandra X-ray Observatory's view of Sagitarrius A is bright spot of light – not something usually associated with theoretical black holes (which after all are black, very dark, and invisible). The light is caused by the emissions of x-ray flares, we are told. Is that the clue? Flares.
Previous research predicted 20,000 small black holes at the core of our galaxy, each on the dining room table to be gobbled up by the massive black hole. Sagittarius A is conveniently surrounded by a halo of gas and dust providing the galaxy with a breeding ground for stars (and presumably black holes). Basically, the study involves a lot of projection – and not enough meant on the bone. All they have detected are a dozen less energetic x-ray bursts which they assume, without anything but theory, have an origin in small black holes – and a dozen seems hardly convincing as 20,000 are projected. Not only that but pulsars also emit x-rays it is thought – so no certainty whatsoever than anything like a black hole has been snared by Chandra. See also https://phys.org/print442041391.html … and https://wattsupwiththat.com/2018/04/08/astronomer-tens-of-thousands-of-b… also has a post on the same subject. Needless to say a lot of modeling was involved – and projection of what they think should be there rather than what may actually be there at the heart of the Milky Way.