new 2nd black hole discovered in the milky way galaxy

Astronomers think they have found a rare if not unique black hole very near the center of the Milky Way. That would make two of the beasts in that part of the galaxy.

The discovery also adds weight to the idea that black holes come in three sizes, essentially small, medium and large.

Stellar black holes -- the remains of collapsed stars, are common. They typically harbor as much mass as a few suns. And for years, scientists have known there are supermassive black holes in many galaxies; one with the mass of more than three million suns anchors the Milky Way.

The newly detected object appears to be an intermediate mass black hole, packing about 1,300 solar masses.

Intermediate mass black holes ought to exist, some theorists say, because they should have been the building blocks of supermassive black holes. A few should be left scattered around any respectable galaxy. But attempts to discover them -- data suggest two others exist in our galaxy -- have so far proved inconclusive
www.space.com