Exploring the bulk of the BL Lac object population: parsec scale radio properties and gamma ray emission

Abstract

BL Lac objects have been found to be the largest population of emitters in gamma-ray band. However, since they are relatively weak radio sources, their parsec scale structure and most of their radio properties are poorly known. To increase our knowledge of the BL Lac object population, we selected a sample of BL Lacs from the BZ Cat at low redshift (z < 0.2), with no constrain on the radio flux density and gamma-ray activity. We present here the results of a first VLBA observation at 8 and 15 GHz and shortly discuss their properties