The Black Hole's Corona: An X-ray Lantern Made of Electron Vapor
A lantern shines through thick fog. Light scatters off water droplets, and the lantern appears blurred. Something similar happens around a black hole: hot gas, like fog, envelops it, while X-rays from the inner parts of the disk struggle through this cloud. Only here, the "droplets" are electrons, and the "fog" itself is called the corona.