Co-precession of a curved jet and compact accretion disk in M87

Abstract

Observational constraints on the configuration of the black hole (BH)-accretion disk-jet system are crucial to understanding BH spin, accretion disk physics, and jet formation. The recently reported variation in the M87 jet position angle (PA) provides a novel avenue to explore these long-standing issues. The observed $\sim$ 11-year periodicity, spanning over two cycles, is consistent with the Lense-Thirring (LT) precession of a compact, tilted accretion disk. However, how such a compact region decouples from the larger-scale accretion flow remains an open question in current numerical simulations. The jet precession challenges the traditional view of a strictly collimated jet, revealing a subtle curvature in the jet's inner regions that dynamically links the jet to the spinning BH and successfully accounts for its unexpectedly wide inner projected profile. While continued long-term observations are needed to distinguish coherent precession from stochastic fluctuations in the disk or jet orientation, these results open a new window for probing BH systems through coordinated multi-scale observations and follow-on theoretical models.