Comparison between $Fermi$ Detected and non-$Fermi$ Detected Superluminal Sources

Active galactic nuclei (AGNs) have been attracting research attention due to their special observable properties. Specifically, a majority of AGNs are detected by Fermi-LAT missions, but not by Fermi-LAT, which raises the question of whether any differences exist between the two. To answer this issue, we compile a sample of 291 superluminal AGNs (189 FDSs and 102 non-FDSs) from available multi-wavelength radio, optical, and X-ray (or even $gamma$-ray) data and Doppler factors and proper motion ($mu$) (or apparent velocity ($beta_{rm{app}}$)); calculated the apparent velocity from their proper motion, Lorentz factor ($Gamma$), viewing angle ($phi$) and co-moving viewing angle ($phi_{co}$) for the sources with available Doppler factor ($delta$); and performed some statistical analyses for both types. Our study indicated that1. In terms of average values, FDSs have higher proper motions ($mu$), apparent velocities ($beta_{rm app}$), Doppler factor ($delta$), Lorentz factor ($Gamma$), and smaller viewing angle ($phi$). Nevertheless, there is no clear difference in co-moving viewing angles ($phi_{rm co}$).