  Where does Hawking radiation originate? A common picture is that it arises
from excitations very near or at the horizon, and this viewpoint has supported
the "firewall" argument and arguments for a key role for the UV-dependent
entanglement entropy in describing the quantum mechanics of black holes.
However, closer investigation of both the total emission rate and the stress
tensor of Hawking radiation supports the statement that its source is a
near-horizon quantum region, or "atmosphere," whose radial extent is set by the
horizon radius scale. This is potentially important, since Hawking radiation
needs to be modified to restore unitarity, and a natural assumption is that the
scales relevant to such modifications are comparable to those governing the
Hawking radiation. Moreover, related discussion suggests a resolution to
questions regarding extra energy flux in "nonviolent" scenarios, that does not
spoil black hole thermodynamics as governed by the Bekenstein-Hawking entropy.
