We present results of EVN observations of eleven GHz-Peaked-Spectrum ( GPS ) radio sources at 2.3/8.4 GHz .
These sources are from the classical ” bright ” GPS source samples with peak flux densities > 0.2 Jy and spectral indices \alpha < -0.2 ( S \propto \nu ^ { - \alpha } ) in the optically thick regime of their convex spectra .
Most of the target sources did not have VLBI images at the time this project started .
The aim of the work is to find Compact Symmetric Object ( CSO ) candidates from the ” bright ” GPS samples .
These CSOs play a key role in understanding the very early stage of the evolution of individual radio galaxies .
The reason for investigating GPS source samples is that CSO candidates are more frequently found among this class of radio sources .
In fact both classes , GPS and CSO , represent a small fraction of the flux limited and flat-spectrum samples like PR+CJ1 ( PR : Pearson-Readhead survey , CJ1 : the first Caltech–Jodrell Bank survey ) and CJF ( the Caltech–Jodrell Bank flat spectrum source survey ) with a single digit percentage progressively decreasing with decreasing flux density limit .
Our results , with at least 3 , but possibly more CSO sources detected among a sample of 11 , underline the effectiveness of our approach .
The three confirmed CSO sources ( 1133+432 , 1824+271 , and 2121 - 014 ) are characterized by a symmetric pair of resolved components , each with steep spectral indices .
Five further sources ( 0144+209 , 0554 - 026 , 0904+039 , 0914+114 and 2322 - 040 ) can be considered likely CSO candidates .
The remaining three sources ( 0159+839 , 0602+780 and 0802+212 ) are either of core-jet type or dominated by a single component at both frequencies .