Sumida, Viktor Y. D.
Schutzer, A. de A.
Total Authors: 4
 Univ Cidade Sao Paulo, Nucleo Astrofis, R Galvao Bueno 868, BR-01506000 Sao Paulo, SP - Brazil
 Univ Cruzeiro Sul, R Galvao Bueno 868, BR-01506000 Sao Paulo, SP - Brazil
 Univ Grenoble Alpes, IPAG, CNRS, F-38000 Grenoble - France
 Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, R Matao 1226, Cidade Univ, BR-05508900 Sao Paulo, SP - Brazil
Total Affiliations: 4
Monthly Notices of the Royal Astronomical Society;
Web of Science Citations:
The physical nature of the mechanism responsible for the emission of neutrinos in active galactic nuclei (AGNs) 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. (AU)