Astronomers find a rare intermediate-mass black hole

Los Angeles Times : Supermassive black holes, up to billions of solar masses in size, are found at the center of most galaxies, making them quite common. Intermediate-mass black holes, which are between 100 and 1 million solar masses, are much rarer. A team of researchers has been studying a galaxy that is home to two central black holes—likely the result of the collision of two galaxies. The researchers have found that one of the two is not surrounded by the usual crowd of stars. The primary black hole has 500 times as many stars around it as the secondary one. The most likely explanation is that the second black hole is not as massive and that the gravity of the larger one stripped the smaller one of many of the stars around it. The discovery may help provide more details about this rare class of objects, which are thought to represent an intermediate point in the life span of black holes.