High Resolution Data on the Cloverleaf in the UV and in CO(7-6): a New Model of the Lens and a Model of the Molecular Region in the Quasar at Z = 2.56

We present a new investigation of the Cloverleaf (z = 2.56) based on the combination of archival HST/WFPC2 data, recent IRAM CO(7-6) maps, and wide field CFHT/FOCAM images. The deep WFPC2 observation (F814W) shows a significant over-density of I_814W 23-25 galaxies around the Cloverleaf that we interpret as the presence of a distant cluster of galaxies along the line of sight. The Cloverleaf is probably the result of the lensing effects of a system which includes, in addition to a single galaxy, one of the most distant clusters of galaxies ever detected. We have modeled the lens accordingly. The high-resolution IRAM/CO map provides for the first time the orientation and the ellipticity of the CO spots induced by the shear component. Velocity - positional effects are detected at the 8 sigma level in the CO map. A strong limit can then be put on the size, shape and location of the CO source around the quasar. The CO source is found to form a disk- or ring-like structure orbiting the central engine at 100 km s^{-1} at a radial distance of 100 pc, leading to a central mass of 10⁹ M_odot possibly in the form of a black hole.