Dzhelepov Laboratory of Nuclear Problems

Date and Time: Thursday, 11 June 2020, at 3:00 PM

Venue: Online conference in Zoom

Seminar topic: “Observational evidence for the origin of high-energy neutrinos in active galactic nuclei: VLBI and RATAN-600”

Speaker: Alexander Victorovich Plavin (Astro Space Center of LPI; MIPT)

Abstract:

Observational information on high-energy astrophysical neutrinos is being continuously collected by the IceCube observatory. However, the sources of neutrinos were still unknown. In our study, we use radio very-long-baseline interferometry (VLBI) data for a complete sample of active galactic nuclei (AGN). We address the problem of the origin of astrophysical neutrinos with energies above 200 TeV. It is found that AGN positionally associated with IceCube events have stronger emission from central regions compared to the rest of the sample. The post-trial probability of a chance coincidence is 0.2%. We select the four strongest AGN as mostly probable associations: 3C 279, NRAO 530, PKS 1741-038, and OR 103. Moreover, we find an increase of radio emission at frequencies above 10 GHz around neutrino arrival times for several other AGN on the basis of RATAN-600 monitoring. The most pronounced example of such behavior is PKS 1502+106. We conclude that AGN with bright Doppler-boosted jets constitute an important population of neutrino sources. High-energy neutrinos are produced in their central parsec-scale regions, probably in proton-photon interactions at or around the accretion disk. A narrow viewing angle is the common reason why both neutrinos and jet emission from AGN are detected.