Astronomy and Astrophysics Supplement Series (ISSN 0365-0138), vol. 94, no. 1, July 1992, p. 37-42.
Takalo, L. O.; Sillanpaa, A.; Nilsson, K.; Kidger, M.; de Diego, J. A.; Piirola, V.
Fecha de publicación:
Results are presented from simultaneous UBVRI photopolarimetric observations of eight blazars at the 2.56-m Nordic Optical Telescope during winter 1991. In 3C 66A the highest ever measured polarization, P(U) = 30.5 percent is observed, with small frequency dependence (FDP), P being lower toward longer wavelengths. In AO 0235 + 164, large changes in the polarization level and in the FDP between different nights were detected. The FDP is seen to be three times more common than the frequency dependence in the position angle in these blazars.