VLBI polarization images of eight compact active galactic nuclei at lambda=1.3 cm

Global VLBI images in intensity and Linear polarization at lambda = 1.3 cm of the BL Lacertae objects 0235+164, 0300+470, 0735+178, 0954+658, 1803+784 , 1823+568, and BL Lac and OW quasar 3C279 are presented and analysed. Thes e are the highest resolution polarization images currently available for se veral of these sources. On the whole, the tendencies observed at longer cen timetre wavelengths are also exhibited in these 1.3-cm images. When core po larization is detected, the corresponding polarization angles chi tend to l ie either parallel or perpendicular to the direction of the inner jet. The core degrees of polarization are usually comparable to those typical at 6 c m, but somewhat lower in several cases, suggesting that the higher resoluti on data are better separating the contributions of intrinsically weakly pol arized cores and highly polarized emerging knots. The observed chi vectors in the jets of 0735+178, 0954+658, 1823+568, BL Lac and 3C279 are aligned w ith the jet, implying the presence of transverse magnetic fields. In 0300+4 70 and BL Lac, there are regions where the direction of chi seems to be nei ther parallel nor perpendicular to the jet; it is not clear whether this is due to genuine obliquity of the magnetic field structure or to inadequate knowledge of the local flow direction.