We present and discuss the results of VLBI ( EVN ) observations of three low-luminosity ( P _ { 5 ~ { } GHz } < 10 ^ { 25 } W Hz ^ { -1 } ) Broad Emission Line AGNs carefully selected from a sample of flat spectrum radio sources ( CLASS ) .
Based on the total and the extended radio power at 5 GHz and at 1.4 GHz respectively , these objects should be technically classified as radio-quiet AGN and thus the origin of their radio emission is not clearly understood .
The VLBI observations presented in this paper have revealed compact radio cores which imply a lower limit on the brightness temperature of about 3 \times 10 ^ { 8 } K. This result rules out a thermal origin for the radio emission and strongly suggests an emission mechanism similar to that observed in more powerful radio-loud AGNs .
Since , by definition , the three objects show a flat ( or inverted ) radio spectrum between 1.4 GHz and 8.4 GHz , the observed radio emission could be relativistically beamed .
Multi-epoch VLBI observations can confirm this possibility in two years time .