Effects of High-Energy Particles on Accretion Flows onto a Supermassive Black Hole

TL;DR

This paper models how high-energy particles influence accretion flows onto supermassive black holes, revealing their limited impact on flow structure but significant energy extraction and potential jet formation implications.

Contribution

It introduces a two-component accretion flow model incorporating high-energy particles and analyzes their effects on flow dynamics and particle luminosities.

Findings

High-energy particles have minimal effect on overall flow structure.

Escaping particles can carry away up to 1% of the accreted mass energy.

High-energy particles may influence relativistic jet production.

Abstract

We study effects of high-energy particles on the accretion flows onto a supermassive black hole and luminosities of escaping particles such as protons, neutrons, gamma-rays, and neutrinos. We formulate a one-dimensional model of the two-component accretion flow consisting of thermal particles and high-energy particles, supposing that some fraction of the released energy is converted to the acceleration of the high-energy particles. The thermal component is governed by fluid dynamics while the high-energy particles obey the moment equations of the diffusion-convection equation. By solving the time evolution of these equations, we obtain advection dominated flows as the steady state solutions. Effects of the high-energy particles on the flow structures turn out to be small even if the pressure of the high-energy particles dominates over the thermal pressure. For a model in which the escaping protons take away almost all the released energy, the high-energy particles have large influence enough to make the flow have the Keplerian angular velocity at the inner region. We calculate the luminosities of the escaping particles for these steady solutions. The escaping particles can extract the energy from about $10^{-4}\dot M c^2$ to $10^{-2}\dot M c^2$, where $\dot M$ is the mass accretion rates. The luminosities of the escaping particles depend on the parameters such as the injection Lorentz factors, the mass accretion rates, and the diffusion coefficients. We also discuss some implications on the relativistic jet production by the escaping particles.