Most galaxies we know of have a supermassive black hole at their cores. These black holes may be millions or billions of times the mass of the Sun, but they are generally proportionate to the size of their host galaxies—or more properly, the central bulge of those galaxies. Up until recently, I wouldn’t have said “generally”, I would have said “always”. However, the compact galaxy NGC 1277 was recently found to have a hugely oversized black hole. Not only is this black hole huge in comparison to its host, it’s one of the most massive yet found.

A new observation has revealed a galaxy that isn’t just bending the rule, but completely breaking it. In most systems, the black hole’s mass is about 0.1 percent of the mass of the galaxy’s central bulge. Remco van den Bosch and colleagues identified a black hole with a mass that’s about 59 percent of the mass of the central bulge. In fact, this black hole is one of the most massive ever observed, a striking discovery in a galaxy much smaller than our own. The galaxy itself is a bit on the small side, and the researchers suggest that we might want to look at the black holes in more galaxies this size. [Read more…]

A big black hole in a small galaxy