Radio core dominance of Fermi-LAT selected AGNs
  Aims. We present a sample of 4388 AGNs with available radio core-dominance
parameters defined as the ratio of the core flux densities to extended ones,
namely, R = Score/Sext., which includes 630 Fermi-detected AGNs respect to the
catalog of 4FGL, the fourth Fermi Large Area Telescope source catalog, and the
rest of them are non-Fermi-detected AGNs. In our sample, 584 blazars are
Fermi-detected and 1310 are not, and also consists of other subclasses such as
Seyfert, Fanaroff-Riley I/II and normal galaxies. We investigate various
different properties between Fermi-detected AGNs and non-Fermi-detected ones by
using the core-dominance parameters as the previous study has shown that R is a
good indication of beaming effect. Methods. We then calculate the radio
spectral indices for whole sample and adopt {\gamma}-ray photon indices for
Fermi AGNs from 4FGL catalog for discussing their different performances on
different subclasses, and obtain the relation between core-dominance parameters
and radio spectral indices for both Fermi and non-Fermi sources according to
the two components model on radio band, which are consistent with our previous
study. Results. We found that the core-dominance parameters and radio spectral
indices are quite different for different subclasses of AGNs, not only for
Fermi sources but also non-Fermi sources, particularly, R for the former ones
is averagely higher than later ones. We also adopt the same relation on
core-dominance parameters and {\gamma}-ray photon indices for Fermi sources by
taking the same assumption with two components model on {\gamma}-ray band, and
obtain the fitting results indicating that the {\gamma}-ray emissions of Fermi
blazars are mainly from the core component, which is perhaps associated with
the beaming effect. Therefore, Fermi blazars are beamed.
