By Ron Cowen
From Atlanta, at a meeting of the American Astronomical Society black holes rank among the most intriguing objects in the universe. Now, astronomers have found a really cool one.
Homing in on the supermassive black hole at the heart of the Andromeda galaxy, the sharp eye of the Chandra X-ray Observatory has found that gas falling into the dense object has a temperature of a few million kelvins. That’s the lowest temperature ever found for emissions from a galactic black hole. Sucking in hot, X-ray-emitting gas at nearly the speed of light, the black holes that scientists have previously studied have temperatures typically of about a billion kelvins.