Imprints of the Lorentz-symmetry breaking on the precessing jet nozzle of M87*

TL;DR

This study uses M87* jet precession observations to constrain black hole parameters in Bumblebee gravity, revealing potential deviations from Kerr black holes and implications for Lorentz-symmetry breaking effects.

Contribution

It models tilted accretion disk orbits in Bumblebee gravity to connect jet precession data with black hole parameters, a novel approach for testing Lorentz-symmetry breaking.

Findings

ISCO and orbit parameters depend on tilt, spin, and Lorentz-violation parameters.

Jet precession period constrains warp radius and black hole parameters.

Comparison with Kerr limits suggests possible non-vacuum Bumblebee black hole signatures.

Abstract

The approximately 11-year jet precession period observed in M87* strongly suggests that the supermassive rotating black hole with a tilted accretion disk, which could provide a powerful constraint for confining the parameters of black hole. In this paper, our aim is to utilize the observations of M87* to preliminarily constrain the parameters of the rotating black hole in Bumblebee gravity by modeling the motion of the tilted accretion disk particle with the spherical orbits. We compute spherical orbits and ISSOs, demonstrating that the conserved quantities energy $\mathcal{E}$, angular momentum $\mathcal{L}$, and Carter constan $\mathcal{K}$ depend on $(r,a,\ell,\zeta)$, exhibiting distinct behaviors for prograde and retrograde orbits. For prograde orbits, the ISSO radius $r_{ISSO}$ decreases with spin parameter $a$ and LSB parameter $\ell$ and increases with the tilt angular $\zeta$, whereas the opposite trends occur for retrograde orbits. Angular analysis shows that $\theta$ oscillates within $(\pi/2-\zeta, \pi/2+\zeta)$, while $\phi$ increases approximately linearly, enabling the determination of the oscillation period $T_\theta$, azimuthal accumulation $\phi(T_\theta)/\pi$, and precession angular velocity $\omega_t$. Using the observed jet precession period $T=11.24 \pm 0.47$ years with a fixed tilt $\zeta=1.25^\circ$, the warp radius $r/M$ ranges from $(5.73,25.15)$ for prograde and $(6.16,26.46)$ for retrograde orbits, increasing with $a$ or $\ell$. Comparisons with Kerr limits ($r/M=14.12$ prograde, $16.1$ retrograde) suggest that $r/M>16$ may indicate a non-vacuum Bumblebee vector field. Incorporating the EHT shadow $\theta_{sh}=42\pm3\mu$as further constrains $r/M$ to $(5.82,22.61)$ and $(6.17,24.74)$, with discrepancies of $0.05\sim1.96$.