  Inhomogeneous fluid flows which become supersonic are known to produce
acoustic analogs of ergoregions and horizons. This leads to Hawking-like
radiation of phonons with a temperature essentially given by the gradient of
the velocity at the horizon. We find such acoustic dumb holes in charged
conformal fluids and use the fluid-gravity correspondence to construct dual
gravity solutions. A class of quasinormal modes around these gravitational
backgrounds perceive a horizon. Upon quantization, this implies a thermal
spectrum for these modes.
