Are CSO host-galaxies undergoing merging?
  The galaxy-type CSO (compact symmetric objects) rate from an intermediate large sample PR+CJ1 is found to be consistent with the Sb-Sb merger rate of 4.6% in redshift z<1. The CSO detection rate seems going down when the sample size is increasing, which could not reach the high merger rate in z>1, yet no deep VLBI sample in z>1 is available now. 
Xiang Liu (Urumqi Astronomical Observatory)