A Sample of Low‐Redshift BL Lacertae Objects. I. The Radio Data

Abstract

We present a new sample of 30 nearby (z < 0.2) BL Lac objects, selected to study the nuclear as well as the large-scale properties of low-power radio sources. In this first paper, we show and discuss new radio data taken with the Very Large Array (19 objects at 1.4 GHz, ei ther in A or C configuration, or both) as well as with the Very Long Baseline Array (15 sources at 5 GHz). On the kiloparsec scale, all objects exhibit a compact core and a variety of radio morphologies (jets, halos, and secondary compact components). On the parsec scale, we find weak cores and a few short, one-sided jets. From the jet/counterjet ratio, core dominance, and synchrotron self-Compton model, we estimate the intrinsic orientation and velocity of the jets. The resulting properties of BL Lac objects are similar to those of a parent population composed of FR I radio galaxies.