Tracing jet–ISM interaction in young AGN: correlations between [O III] λ 5007 Å and 5-GHz emission

Abstract

Aims. I study the interaction between young AGN and their host galaxies based on their ionized gas and radio emission, and analyze possible implications for radio galaxy evolution. Methods. The [O III] lambda 5007 angstrom line and 5-GHz radio properties are compared and studied for a large, representative sample of GPS and CSS (i.e., young) quasars and radio galaxies, and large-scale sources using [O III] lambda 5007 angstrom line and 5-GHz radio data from the literature and our own observations. Results. Several correlations between the [O III] lambda 5007 angstrom line and 5-GHz radio emission were found. The main result is that the [O III] lambda 5007 angstrom emission is strongly correlated with the GPS/CSS source size, which indicates that the [O III] lambda 5007 angstrom emission is enhanced significantly by the jet expansion through the host galaxy ISM. Shocks are the most likely enhancement mechanism, although jet-induced star formation could be also, partly, responsible for the [O III] lambda 5007 angstrom emission. The data also suggests that the jet possibly decelerates as it grows, although the correlation expansion speed versus radio size is weak.