Hawking radiation is black body radiation which is emitted by black holes, due to quantum effects near the event horizon. It is named after the physicist Stephen Hawking, who provided a theoretical argument for its existence in 1974.
Hawking radiation reduces the mass and the energy of the black hole and is therefore also known as black hole evaporation. Because of this, black holes that lose more mass than they gain through other means are expected to shrink and ultimately vanish.
Hawking radiation is such a small effect that it has never been measured. Micro black holes (MBHs) are predicted to be larger net emitters of radiation than larger black holes (and should thus shrink and dissipate faster), but MBHs have yet to be observed.