  We present a Chandra X-ray observation of G12.82-0.02, a shell-like radio
supernova remnant coincident with the TeV gamma-ray source HESS J1813-178. We
resolve the X-ray emission from the co-located ASCA source into a compact
object surrounded by structured diffuse emission that fills the interior of the
radio shell. The morphology of the diffuse emission strongly resembles that of
a pulsar wind nebula. The spectrum of the compact source is well-characterized
by a power-law with index approx. 1.3, typical of young and energetic
rotation-powered pulsars. For a distance of 4.5 kpc, consistent with the X-ray
absorption, the 2-10 keV X-ray luminosity of the putative pulsar and nebula is
L(PSR) = 3.2E33 erg/s and L(PWN) = 1.4E34 erg/s, respectively. Both the flux
ratio of L(PWN)/L(PSR) = 4.3 and the total luminosity of this system imply a
pulsar spin-down power greater then 1E37 erg/s, on a par with the top ten most
energetic young pulsars in the Galaxy. We associate the putative pulsar with
the radio remnant and the TeV source and discuss the origin of the gamma-ray
emission.
