We report four novel position angle measurements of the core region of M81* at 5GHz and 8GHz, which confirm the presence of sinusoidal jet precession of the M81 jet region as suggested by \cite{Marti-Vidal2011}. The model makes three testable predictions on the evolution of the jet precession, which we test in our data with observations in 2017, 2018, and 2019. Our data confirms a precession period of ∼7yr on top of a small linear drift. We further show that two 8 GHz observation are consistent with a precession period of ∼7yr, but show a different time-lag w.r.t. to the 5 GHz and 1.7 GHz observations. We do not find a periodic modulation of the light curve with the jet precession, and therefore rule out a Doppler nature of the historic 1998-2002 flare. Our observations are consistent with either a binary black hole origin of the precession or the Lense-Thirring effect.
@article{arxiv.2303.00603,
title = {Radio jet precession in M81*},
author = {S. D. von Fellenberg and M. Janssen and J. Davelaar and M. Zajaček and S. Britzen and H. Falcke and E. Körding and E. Ros},
journal= {arXiv preprint arXiv:2303.00603},
year = {2023}
}