Accretion discs around black holes
Matter gets sucked towards a black hole
A black hole can rip matter away from a normal star if that star gets a bit too close to the black hole. This matter spirals into towards the black hole, getting very hot as it does so. This spiralling structure is thought to take the form of a disc, and is thought to play a crucial role in the launch of jets squirted away from near the black holes.
Sometimes these accretion disc give rise to winds of outflowing matter, gusting away from the disc. Optical spectroscopy is a powerful tool to follow this and all the types of mass outflows that are seen from black holes.