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