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 position angle of the M87 jet provides a new avenue for exploring these long-standing issues. The observed ~11-year periodicity, spanning over two cycles, is consistent with the Lense–Thirring 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 by revealing a subtle curvature in the inner regions of the jet that dynamically links the jet to the spinning BH and successfully accounts for its unexpectedly wide inner projected profile. Although 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 multiscale observations and follow-on theoretical models.