  We present H- and Ks-band imaging data resolving the gap in the transitional
disk around LkCa 15, revealing the surrounding nebulosity. We detect sharp
elliptical contours delimiting the nebulosity on the inside as well as the
outside, consistent with the shape, size, ellipticity, and orientation of
starlight reflected from the far-side disk wall, whereas the near-side wall is
shielded from view by the disk's optically thick bulk. We note that
forward-scattering of starlight on the near-side disk surface could provide an
alternate interpretation of the nebulosity. In either case, this discovery
provides confirmation of the disk geometry that has been proposed to explain
the spectral energy distributions (SED) of such systems, comprising an
optically thick outer disk with an inner truncation radius of ~46 AU enclosing
a largely evacuated gap. Our data show an offset of the nebulosity contours
along the major axis, likely corresponding to a physical pericenter offset of
the disk gap. This reinforces the leading theory that dynamical clearing by at
least one orbiting body is the cause of the gap. Based on evolutionary models,
our high-contrast imagery imposes an upper limit of 21 Jupiter masses on
companions at separations outside of 0.1" and of 13 Jupiter masses outside of
0.2". Thus, we find that a planetary system around LkCa 15 is the most likely
explanation for the disk architecture.
