Speaker: Monica Orienti (INAF)
The evolutionary stage of a powerful radio source originated by an AGN is related to its linear size. In this context, compact symmetric objects (CSOs), which are powerful and intrinsically small objects (<1 kpc), should represent the young stage in the individual radio source life. Following the evolution models, these objects would evolve into the population of classical radio galaxies. However, the fraction of young radio sources in flux density-limited sample is much larger than what expected from the number counts of large radio sources, suggesting the existence of short-lived radio sources.
In this presentation I will discuss the physical conditions of young radio sources on the basis of high resolution radio observations. In particular I will present preliminary results of VLBI observations of a sub-sample of extreme GPS sources that should be at the very beginning of their radio evolution. Furthermore, I will discuss preliminary results on VLBA and JVLA observations of a sample of short-lived radio source candidates and discuss their properties in the context of the radio source evolution.