Polarization microvariability studies of BL Lac objects

ANDRUCHOW, I.; CELLONE, S. A.; ROMERO , G. E.

Congreso; Reunion Anual de la Asociacion Argentina de Astronomia; 2003

We report the results of a systematic campaign devoted to determine the incidence of microvariability in the optical polarization of BL Lac objects. We have observed a sample formed by 8 X-ray selected (XBL) and 10 radio-selected (RBL) sources, in addition to the quasar 3C279, searching for rapid changes in both the degree of linear polarization and the corresponding polarization angle. The statistical properties of both classes of objects are compared and some general conclusions on the nature of these phenomena are drawn.