CORRELATIONS BETWEEN THE VLBI AND OPTICAL POLARIZATION OF BL LACERTAEOBJECTS

One of the most promising approaches to unravelling the relationship b etween the optical and radio emission in AGN is to obtain nearly simul taneous optical polarization and VLBI polarization data. We present he re such data for the three BL Lacertae objects 1147+245, 1418+546, and 1749+096 obtained during a lambda=6 cm VLBI polarization run at epoch 1992 March. In each of these three sources, the optical polarization position angle is aligned with the radio polarization position angle e ither in the VLBI core or in a VLBI jet component that is barely resol ved from the core, Together with similar results presented earlier for an additional 4 BL Lacertae objects and the OVV quasar 3C 279, these results strongly indicate that the optical and radio polarized emissio n in these sources are linked to a much greater extent than has usuall y been expected, There is also a hint that the optical and VLBI degree s of polarization may be positively correlated, though more data are n eeded to confirm this. These results suggest that either the emission at these two frequencies is co-spatial or that the source geometry is quite uniform over long distances. The available data suggest that the strong optical polarization in these sources is associated with the f ormation and emergence of compact new VLBI components. (C) 1996 Americ an Astronomical Society.