Chandra finds "cool" black hole at heart of Andromeda Galaxy

A team of scientists from the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass., reported that the gas funneling into a supermassive black hole in the heart of the Andromeda Galaxy, designated as "M31," is a "cool" million degrees Celsius. This unexpected result adds one more quirk to the strange behavior previously observed at the center of M31. NASA's Chandra X-ray Observatory took its first X-ray picture of the Andromeda Galaxy on Oct. 13, 1999. More than 100 individual X-ray sources were seen. One of these sources was at the previously determined position of the central supermassive black hole, which has the mass of 30 million suns. With many X-ray emitting stars in the center of M31 there was a slight chance that one of them might be at this position just by coincidence. The low temperature of the suspected central source, as compared to the other sources, gave the team the clue they needed.