Middleweight black holes were thought to be hiding in globular clusters
For black holes, there appears to be very little room for mediocrity, astronomers have found.
A study suggests they come in either small or large sizes, but medium-sized ones are very rare or non-existent. A team of astronomers has examined one of the best hiding places for a middleweight black hole, and found that it cannot possibly host one. Details of the research are to be published in the latest issue of the Astrophysical Journal. – bbc