Although black holes are invisible, they can be found by watching their effect on nearby gas and stars. For stellar-mass black hole IGR J17091, this is exactly what is happening. Its gravity is pulling gas away from a companion star and this gas has formed into a disk around the black hole, which is driving off wind.
However, there's something special about IGR J17091--the wind it's creating is the fastest wind ever discovered blowing off a disk surrounding a stellar-mass black hole.
In most other ways IGR J17091 is pretty much a ho-hum black hole: it's located … Read more