  The nature and energetics of feedback from thermal winds in quasars can be
constrained via observations of the Sunyaev-Zeldovich Effect (SZE) induced by
the bubble of thermal plasma blown into the intergalactic medium by the quasar
wind. In this letter, we present evidence that we have made the first detection
of such a bubble, associated with the hyperluminous quasar HE0515-4414. The SZE
detection is corroborated by the presence of extended emission line gas at the
same position angle as the wind. Our detection appears on only one side of the
quasar, consistent with the SZE signal arising from a combination of thermal
and kinetic contributions. Estimates of the energy in the wind allow us to
constrain the wind luminosity to the lower end of theoretical predictions,
~0.01% of the bolometric luminosity of the quasar. However, the age we estimate
for the bubble, ~0.1 Gyr, and the long cooling time, ~0.6 Gyr, means that such
bubbles may be effective at providing feedback between bursts of quasar
activity.
