  A wind nebula generating extended X-ray emission was recently detected
surrounding Swift 1834.9-0846. This is the first magnetar for which such a
(pulsar) wind nebula (PWN) was found. I demonstrate that Swift 1834.9-0846's
nebula can be rotationally-powered if it is being compressed by the
environment. The physical reason behind this is the dominance of adiabatic
heating over all other cooling and escape processes. This effect can happen
only for pulsars of relatively low spin-down power and can make for very
efficient nebulae. This contribution is based on previous work published in ApJ
835, article id. 54, 13 pp. (2017).
