  The physical nature of the mechanism responsible for the emission of
neutrinos in active galactic nuclei (AGN) has been matter of debate in the
literature, with relativistic jets of radio-loud AGNs as possible candidates to
be the sources of high energy neutrinos. The most prominent candidate so far is
the blazar TXS 0506+056, which is found to be associated with the neutrino
event IceCube-170922A. Furthermore, the IceCube reported an excess of neutrinos
towards TXS 0506+056 between September 2014 and March 2015, even though this
association needs additional investigation, considering the presence of a
nearby gamma-ray source, the quasar PKS 0502+049. Motivated by this, we studied
the parsec-scale structures of TXS 0506+056 and PKS 0502+049 through radio
interferometry at 8 and 15\,GHz. We identified twelve jet components in TXS
0506+056 and seven components in PKS 0502+049. The most reliable jet components
show superluminal speeds ranging from 9.5c to 66c in the case of TXS 0506+056,
and from 14.3c to 59c for PKS 0502+049, which were used to estimate a lower
(upper) limit for the Lorentz factor (jet viewing angle) for both sources. A
novel approach using simultaneously the brightness temperature of the core
region and the apparent speeds of the jet components allowed us to infer basic
jet parameters for TXS 0506+056 at distinct epochs. We also found that the
emergence of new jet components coincides with the occurrence of gamma-ray
flares. Interestingly, two of these coincidences in the case of PKS 0502+049
and one for TXS 0506+056 seems to be correlated with neutrino events detected
by the IceCube Observatory.
