The outburst came from a black hole in the spiral galaxy M83, about 15 million light-years away from Earth. Using NASA's Chandra X-ray Observatory, astronomers found a new object, called an ultraluminous X-ray source (ULX), that emits more X-rays than most "normal" systems in which a companion star orbits around a black hole or neutron star, the researchers said. The observations from Chandra spanned several years, and scientists noticed that the ULX in M83 increased its X-ray brightness by at least 3,000 times.