Search

We present preliminary results from imaging and spectroscopy of a complete sample of radio quasars selected from the B2 survey. The optical data, which provide us information on the environment around the quasars, as well as the redshifts, allow us to address several questions related to the origin and evolution of the radio quasars population. Using VLA observations of the sources we investigate the radio morphology and distortions of these low-luminosity radio quasars. We compare these properties with those of powerful radio quasars.

We present a large program of CCD imaging of low-luminosity radio galaxies selected from the B2 survey of radio sources. We aim to study their optical properties: brightness profiles, isophotal distortions, morphological peculiarities. As the sample contains jet and no-jet sources, this investigation will allow us to compare both populations of low-luminosity radio galaxies. In particular, we will study the local environment and test whether the galaxy density around radio sources plays an important role on the presence of jets or not. The analysis of morphological distortions on the host galaxies will provide us with detailed information on past or recent galaxy encounters.

CCD photometry of the jet in the Thuan-Gunn r and g filters obtained under good seeing conditions is presented. Elliptical models of the underlying stellar emission were subtracted from the reduced and calibrated images. The high signal to noise ratio and good spatial resolution make it possible to determine very accurately the morphological properties of the jet. These observations reveal a number of new features: the outermost knot (H) can be resolved into several components, and the spectral index of the knots between the r and g bands is in general steeper than in that in the radio and shows a trend to become steeper with distance from the nucleus. The implications of these results for current radiation jet models will be briefly discussed.