# RADs energetics and constraints on emerging tori collisions around super-massive Kerr Black Holes

## TL;DR

This paper investigates the configurations, stability, and collision energetics of two coplanar tori orbiting a Kerr black hole, highlighting how black hole spin influences collision energy and the conditions for dual torus accretion.

## Contribution

It provides the first detailed analysis of two-tori configurations around Kerr black holes, including stability, collision energetics, and the impact of black hole spin on these phenomena.

## Key findings

- Collision energy increases with black hole spin.
- Two tori can only coexist under specific conditions.
- Unstable phases of tori are linked to high-energy phenomena.

## Abstract

We provide constraints on possible configurations and interactions of two coplanar tori orbiting a central Kerr black hole (BH), in dependence on its dimensionless spin. The two-tori configurations can be directly linked to the current models featuring the obscuration of galactic BH X-ray emission. The emergence of each torus instability phases is discussed and tori collision has been also investigated. The first simple evaluation of the center-of-mass energy proves that collision-energy-efficiency increases with the dimensionless BH spin. We explore the phenomenological aspects of the corotating and counterrotating tori by analyzing properties of the orbiting toroidal configurations related to the fluid enthalpy flux, the mass-flux, the mass-accretion-rates, and the cusp luminosity in the two cases of corotating and counterrotating fluids in dependence on the SMBH spin. The analysis resulted ultimately in a comparative investigation of the properties of corotating versus counterrotating tori, demonstrating that two accretion tori can orbit around the central Kerr attractor only under very specific conditions. Our results also demonstrate that the dynamics of the unstable phases of these double tori systems is significant for the high energy phenomena which could be observable in the X-ray emission and extremely energetic phenomena in active galactic nuclei and quasar.