Dichotomy in the population of young AGN: optical, radio and X-ray properties

TL;DR

This paper investigates the evolution of young radio-loud AGN, revealing that individual factors like ambient medium interaction and AGN power influence their development, with only the strongest sources likely becoming large-scale radio galaxies.

Contribution

The study introduces new radio, optical, and X-ray data on low luminosity compact AGN, highlighting personalized evolutionary paths and factors determining their growth into large-scale radio sources.

Findings

Evolutionary paths are highly individualized.

Interaction with ambient medium influences AGN development.

Only strong, high excitation AGN likely evolve into large FRII radio sources.

Abstract

There are numerous examples of radio sources with various sizes which surprisingly exhibit very similar morphology. This observational fact helped to create a standard evolutionary model in which young and small radio-loud active galactic nuclei (AGN) called gigahertz-peaked spectrum (GPS) sources and compact steep spectrum (CSS) sources, become large-scale radio objects. However, many details of this evolutionary process are still unclear. We explored evolution scenarios of radio-loud AGN using new radio, optical and X-ray data of so far unstudied low luminosity compact (LLC) sources and we summarize the results in this paper. Our studies show that the evolutionary track is very 'personalized' although we can mention common factors affecting it. These are interaction with the ambient medium and AGN power. The second feature affects the production of the radio jets which if they are weak are more vulnerable for instabilities and disruption. Thus not all GPS and CSS sources will be able to develop large scale morphologies. Many will fade away being middle-aged (10^5 years). It seems that only radio strong, high excitation compact AGN can be progenitors of large-scale FRII radio sources.