  We present Gemini Planet Imager (GPI) adaptive optics near-infrared images of
the giant planet-forming regions of the protoplanetary disk orbiting the nearby
(D = 54 pc), pre-main sequence (classical T Tauri) star TW Hydrae. The GPI
images, which were obtained in coronagraphic/polarimetric mode, exploit
starlight scattered off small dust grains to elucidate the surface density
structure of the TW Hya disk from 80 AU to within 10 AU of the star at 1.5 AU
resolution. The GPI polarized intensity images unambiguously confirm the
presence of a gap in the radial surface brightness distribution of the inner
disk. The gap is centered near 23 AU, with a width of 5 AU and a depth of 50%.
In the context of recent simulations of giant planet formation in gaseous,
dusty disks orbiting pre-main sequence stars, these results indicate that at
least one young planet with a mass 0.2 M_J could be present in the TW Hya disk
at an orbital semi-major axis similar to that of Uranus. If this (proto)planet
is actively accreting gas from the disk, it may be readily detectable by GPI or
a similarly sensitive, high-resolution infrared imaging system.
