CCD photometry of 14 BL Lacertae objects and theoretical model

Abstract

We present the results of monitoring, over a period of 1 year, a sample of 14 BL Lac objects in BVRI bands. Seven sources exhibit short time-scale variability, and five sources exhibit medium time-Scale variability with large amplitude. The evidence of relativistic beaming and accretion disks for 10 BL Lac objects is discussed.