Tori sequences as remnants of multiple accreting periods of Kerr SMBHs

TL;DR

This paper investigates how multiple accretion episodes onto Kerr supermassive black holes leave observable remnants like toroidal structures and instabilities, revealing the black holes' accretion history and spin characteristics.

Contribution

It introduces a relativistic hydrodynamic model to analyze the formation and stability of multiple accreting tori around Kerr SMBHs, highlighting the impact of spin and rotation on observable features.

Findings

Sequences of accreting tori depend on black hole spin and fluid rotation.

Instabilities such as collisions and jet formations are characterized by specific configurations.

Observable remnants can trace the multi-accretion history of SMBHs.

Abstract

Super-massive black holes (SMBHs) hosted in active galactic nuclei (AGNs) can be characterized by multi-accreting periods as the attractors interact with the environment during their life-time. These multi-accretion episodes should leave traces in the matter orbiting the attractor. Counterrotating and even misaligned structures orbiting around the SMBHs would be consequences of these episodes. Our task in this work is to consider situations where such accretions occur and to trace their remnants represented by several toroidal accreting fluids, corotating or counterrotating relative to the central Kerr attractor, and created in various regimes during the evolution of matter configurations around SMBHs. We focus particularly on the emergence of matter instabilities, i.e., tori collisions, accretion onto the central Kerr black hole, or creation of jet-like structures (proto-jets). Each orbiting configuration is governed by the general relativistic hydrodynamic Boyer condition of equilibrium configurations of rotating perfect fluid. We prove that sequences of configurations and hot points, where an instability occurs, characterize the Kerr SMBHs, depending mainly on their spin-mass ratios. The occurrence of tori accretion or collision are strongly constrained by the fluid rotation with respect to the central black hole and the relative rotation with respect to each other. Our investigation provides characteristic of attractors where traces of multi-accreting episodes can be found and observed.