Dense Plasma Torus in the GPS Galaxy NGC 1052

We report results from nearly simultaneous pentachromatic VLBI observations towards a nearby GPS galaxy NGC 1052. The observations at 1.6 and 4.8GHz with the VSOP, and at 2.3, 8.4, and 15.4GHz with VLBA, provide linear resolutions of ~0.1pc. Convex spectra of a double-sided jet imply that synchrotron emission is obscured through foreground cold dense plasma, in terms of free-free absorption (FFA). We found a central condensation of the plasma which covers about 0.1 and 1pc of the approaching and receding jets, respectively. A simple model with a geometrically thick plasma torus perpendicular to the jets is established to explain the asymmetric distribution of FFA opacities.