Abstract

Contributed Talk - Splinter Multimessenger

Thursday, 12 September 2024, 14:55   (S25)

Probes of Jet Physics in Neutrino-Candidate Blazars with cm- and mm-VLBI

F. Eppel [1,2], M. Kadler [1], J. Heßdörfer [1,2], F. Rösch [1,2], E. Ros [2], P. Benke [2], B. Boccardi [2], S. Buson [1], P. Edwards [3], C. Fromm [1], M. Giroletti [4], A. Gokus [5], J. L. Gomez [6], S. Hämmerich [7], D. Kirchner [1], Y. Y. Kovalev [2], T. P. Krichbaum [2], M. Lister [8], K. Mannheim [1], F. McBride [9], C. Nanci [4], R. Ojha [10], G. F. Paraschos [2], M. Perucho [11], A. Plavin [12], A. C. S. Readhead [13], J. Stevens [3], P. Torne [14]
[1] JMU Würzburg, [2] MPIfR Bonn, [3] CSIRO, [4] INAF Bologna, [5] WUSTL, [6] IAA Granada, [7] Dr. Karl-Remeis Observatory Bamberg, [8] Purdue University, [9] Bowdoin College, [10] NASA Goddard Space Flight Center, [11] University of Valencia, [12] Harvard University, [13] Caltech, [14] IRAM

In recent years, evidence has accumulated that some high-energy cosmic neutrinos may be associated with blazars. The strongest evidence for an individual association was found in the case of the blazar TXS 0506+056 which exhibited a major multi-wavelength flare coinciding with an IceCube neutrino event in 2017. A major open question is the production site of neutrinos in blazar jets, especially the possible seed photon fields needed for the hadronic processes are not well constrained. VLBI observations can constrain the jet geometry, magnetic field and Doppler factor in AGN jets to gain insights into the possible neutrino production regions. We have performed a multi-frequency VLBI study from 15 GHz up to 86 GHz on TXS 0506+056 and two additional neutrino-candidate blazars (PKS 0215+015, PKS1502+106) to study the radio structure of neutrino-candidate blazars. We have obtained target of opportunity observations with the VLBA for all three sources within ~1 month from the associated neutrino event and are performing multi-epoch studies on the jet kinematics at 15 GHz as part of the MOJAVE program. Here, we present first results on the contemporary parsec-scale jet morphology of all three sources in total intensity and polarization to constrain possible physical processes leading to neutrino production in blazars.