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Published online by Cambridge University Press: 25 May 2016
In the unified schemes of AGNs BL Lac objects are believed to be Fanaroff-Riley (FR) type I radio galaxies with a relativistic jet aligned to the observer's line of sight (e.g. Urry & Padovani 1995). Kollgaard et al. (1992) and Owen et al. (1995) suggest some FR II sources can also be BL Lac parents. Clearly, isotropic properties such as the galaxy environment of both beamed and unbeamed objects should be identical.