Похоже, что черные дыры промежуточных масс таки существуют

http://arxiv.org/abs/1311.6918
arXiv:1311.6918 [pdf, ps, other]
Radio Detections During Two State Transitions of the Intermediate Mass Black Hole HLX-1
Natalie Webb, David Cseh, Emil Lenc, Olivier Godet, Didier Barret, Stephane Corbel, Sean Farrell, Rob Fender, Neil Gehrels, Ian Heywood
Comments: 13 pages, includes supplementary online information. Published in Science in August 2012
Journal-ref: 2012, Science, 337, 554
Subjects: High Energy Astrophysical Phenomena (astro-ph.HE)

Relativistic jets are streams of plasma moving at appreciable fractions of the speed of light. They have been observed from stellar mass black holes ($\sim$3$-$20 solar masses, M$_\odot$) as well as supermassive black holes ($\sim$10$^6$$-$10$^9$ M$_\odot$) found in the centres of most galaxies. Jets should also be produced by intermediate mass black holes ($\sim$10$^2$$-$10$^5$ M$_\odot$), although evidence for this third class of black hole has until recently been weak. We report the detection of transient radio emission at the location of the intermediate mass black hole candidate ESO 243-49 HLX-1, which is consistent with a discrete jet ejection event. These observations also allow us to refine the mass estimate of the black hole to be between $\sim$9 $\times$10$^{3}$ M$_\odot$ and $\sim$9 $\times$10$^{4}$ M$_\odot$.

(об ультрамощных источниках см. старое, но популярное на русском тут http://www.astronet.ru/db/msg/1202758)