THE INTRADAY VARIABILITY IN THE RADIO-SELECTED AND X-RAY-SELECTED BL LACERTAE OBJECTS

Seven BL Lac objects have been photometrically observed in an effort t o study the difference of optical intraday variability between the rad io-selected BL Lac objects (RBLs) and X-ray-selected BL Lac objects (X BLs). The objects we observed are selected arbitrarily. They are four RBLs; PKS 0735+178. PKS 0754+101, OJ 287 and BL Lac, and three XBLs, H 0323+022, H 0548-322 and H 2154-304. During the observation all of th em exhibited microvariation. and H 0323+022 and H 0548-322 sometimes s howed brightness oscillation. PKS 0735+178 and BL Lac were in their fa int states and not very active. It seems that RBLs do not show microva riability more frequently than XBLs.