Circumbinary disks around T Tauri stars: HST/NICMOS near-infrared images and polarimetric maps

We have obtained new near-infrared images of both GGTau and UYAur circumbinary disks with the polarimetric modes of NICMOS aboard the Hubble Space Telescope. The 1μm intensity map of GGTau reveals a more complete elliptical shape than in previous ground-based images. Its eastern and western sides are definitely asymmetric. Our image strongly supports the ring geometry proposed by Guilloteau, Dutrey & Simon (1999) on the basis of their millimetre interferometry images: a geometrically thick and sharply edged ring surrounding an empty gap around the binary. Around UYAur, we identify structures that are in excellent agreement with the optical images of Ménard et al. (1999), which confirms that the inclination of the system to the line-of-sight is about 60 degrees. We also find tentative new structures closer to the stars.