An extraordinary outburst produced by a black hole in a nearby galaxy has provided direct evidence for a population of old, volatile stellar black holes.
The discovery, made by astronomers using data from NASA's Chandra X-ray Observatory, provides new insight into the nature of a mysterious class of black holes that can produce as much energy in X-rays as a million suns radiate at all wavelengths.
Researchers used Chandra to discover a new ultraluminous X-ray source, or ULX.
These objects give off more X-rays than most binary systems, in which a companion star orbits the remains of a collapsed star. These collapsed stars form either a dense core called a neutron star or a black hole.
The extra X-ray emission suggests ULXs contain black holes that might be much more massive than the ones found elsewhere in our galaxy.
