A search for binary black hole candidates from the VLBI images of AGNs
  We have searched the core-jets pairs in the VLBI scales ($<$1 kpc), from
several VLBI catalogues, and find out 6 possible binary black hole (BBH)
candidates. We present the search result and analyze the candidates
preliminarily, and further study with multi-band VLBI observation and optical
line investigation would be carried out in the future.
