Talk detail

Participant	Kun, Emma
Institution	University of Szeged, Institute of Physics - Dóm tér 9. - Szeged - - Hungary

Session	AC3	Accepted		Order	Time
Talk	Oral abstract	Title	The evolution of the jet of S5 1803+784 identified from very long baseline radio interferometry
Coauthors
Abstract	I discuss observable properties of the flat-spectrum jets of active galactic nuclei, focusing on the evolution of their structure, as revealed by very long baseline interferometry in radio frequencies. As an example I analyse an interesting source, the jet of BL Lac object S5 1803+784 at z = 0.679. Its VLBI observations spanning over two decades show that in contrast to what has been observed in the majority of other VLBI jets, the components building up its surface brightness distribution do not exhibit outward motion, but rather they maintain globally the same position. The long-term behaviour of the ridge line suggests that the jet experiences an oscillatory motion on a time-scale of about 6 years, superposed onto its helical jet kinematics. The temporal variability in the Doppler boosting of the ridge line results in jet regions behaving as flaring "radio lanterns".
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Session	HE6	Accepted		Order	Time
Talk	Oral abstract	Title	Radio and high-energy neutrino emission of the blazar PKS 0723-008
Coauthors
Abstract	In the emerging multi-messenger era of astronomy, the origin of cosmic high-energy (HE) neutrinos detected by the IceCube Neutrino Observatory stays in the forefront of interest of both astronomy and particle physics communities. We identify the source of the HE neutrino event ID5 as the blazar PKS 0723-008. This blazar exhibited a fivefold increase in its radio flux density through the last decade, indicating the plowing of a new jet channel four years before the HE neutrino emission and increasing ever since. We propose a scenario of binary supermassive black hole (SMBH) evolution leading to the observed HE neutrino emissions. I discuss mechanisms of related gravitational wave (GW), neutrino and electromagnetic emission from the coalescence of a binary SMBH and its afterlife. Identification of these sources, beside sought-for HE neutrino detections, is also important for breaking degeneracies in GW parameter estimation and in calibrating the expected abundance of these GW sources.
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