Sub-parsec radio cores in nearby Seyfert galaxies

摘要: We present a census of sub-pc scale properties the VLBI cores in complete sample local Seyfert galaxies. Seventeen out 23 sources with VLA detection are detected also at 1.7 GHz and/or 5 GHz, an average monochromatic radio luminosity log [P (5\, GHz) W Hz^{-1} = 19.4. Radio heterogeneous nature, majority them showing elongated structures or accompanied by extra components, broad ranges brightness temperatures (10^{5}-10^{10} K) and spectral indices (from steep to highly inverted). Interestingly, rate (26%) water maser emission is considerably higher than that found previous surveys (around 10%), suggesting distance biases could significantly affect our knowledge actual occurrence this phenomenon. The observational type 1 2 nuclei similar except for T_{B}, which on 1. These results suggest both thermal non-thermal common low AGN, prevalence free-free processes among cores, likely associated molecular gas. Though limited number statistics, we find no significant correlation between nuclear X-ray luminosity, latter appears be more connected tens pc scales emission, rather scales, particularly most luminous sources. radio-loudness parameter R_{X} L (6cm)/L(2-10 keV), very ( -4.8), comparatively largest black hole masses lowest Eddington ratios, although power does not appear depend accretion rate.