Observational evidence of spin-induced precession in active galactic   nuclei
  We show that it is possible to explain the physical origin of jet precession in active galactic nuclei (AGNs) through the misalignment between the rotation axes of the accretion disk and of the Kerr black hole. We apply this scenario to quasars, Seyfert galaxies and also to the Galactic Center black hole Sgr A*, for which signatures of either jet or disk precession have been found. The formalism adopted is parameterized by the ratio of the precession period to the black hole mass and can be used to put constraints to the physical properties of the accretion disk as well as to the black hole spin in those systems. 
Anderson Caproni (IAG/USP) Herman J. Mosquera Cuesta (ICRA-BR/CBPF)   Zulema Abraham (IAG/USP)