The Impact of Southern-Hemisphere VLBI Blazar Observations on Neutrino Astronomy

The origin of high-energy cosmic neutrinos detected by the IceCube observatory is a hotly debated topic in astroparticle physics. Evidence is accumulating that some of these neutrinos can be associated with AGN and especially with blazars. Several recent studies have revealed a statistical correlation between radio-bright AGN samples and IceCube neutrino event catalogs. In addition, a growing number of individual high-energy neutrinos have been found to coincide with individual radio-flaring blazars. These observational results strongly call for high-quality, high angular-resolution radio observations of such neutrino-associated blazars to study their parsec-scale jet structures. TANAMI is the only large and long-term VLBI monitoring program that focuses on the Southern sky. Within TANAMI, we put a focus on Southern IceCube neutrino-candidate blazars at the S and X band. Here, we present first results of these S-band observations. The rapidly growing KM3NeT, located in the Mediterranean sea, is joining IceCube, located at the south pole, in yielding complementary neutrino data in both hemispheres. This further increases the importance of southern-hemisphere radio monitoring programs of neutrino-associated blazars, like TANAMI.