ABSTRACT

BL Lacertae objects are an enigmatic group of ACTIVE GALACTIC NUCLEI (AGN) characterized by compact, flat-spectrum radio sources, nearly featureless and polarized optical continua, very luminous high-energy radiation (e.g. some BL Lacs are the only celestial detections at TeV energies; Macomb et al 1995) and rapid variability in all observed wavebands