The Jets and Disc of SS 433 at Super-Eddington Luminosities

TL;DR

This study uses advanced radiation hydrodynamical simulations to explore the behavior of SS 433's jets and disc at super-Eddington luminosities, revealing instabilities and variability consistent with observations.

Contribution

It provides the first detailed 2D radiation hydrodynamical models of SS 433's supercritical accretion disc and jets, explaining observed variability and jet properties.

Findings

Jets and disc luminosities match observed rates.

Disc instability causes luminosity modulations and QPOs.

Inner disc transitions from radiation-pressure to gas-pressure dominance.

Abstract

We examine the jets and the disc of SS 433 at super-Eddington luminosities with 600 times Eddington critical accretion rate by time-dependent two-dimensional radiation hydrodynamical calculations, assuming alpha-model for the viscosity. One-dimensional supercritical accretion disc models with mass loss or advection are used as the initial configurations of the disc. As a result, from the initial advective disc models with alpha =0.001 and 0.1, we obtain the total luminosities 2.5x10^{40} and 2.0x10^{40} erg/s. The total mass-outflow rates are 4x10^{-5} and 10^{-4} solar-mass/yr and the rates of the relativistic axial outflows in a small half opening angle of 1 degree are about 10^{-6} solar-mass/yr: the values generally consistent with the corresponding observed rates of the wind and the jets, respectively. From the initial models with mass loss but without advection, we obtain the total mass-outflow and axial outflow rates smaller than or comparable to the observed rates of the wind and the jets respectively, depending on alpha. In the advective disc model with alpha=0.1, the initially radiation-pressure dominant, optically thick disc evolves to the gas-pressure dominated, optically thin state in the inner region of the disc, and the inner disc is unstable. Consequently, we find remarkable modulations of the disc luminosity and the accretion rate through the inner edge. These modulations manifest themselves as the recurrent hot blobs with high temperatures and low densities at the disc plane, which develop outward and upward and produce the QPOs-like variability of the total luminosity with an amplitude of a factor of 2 and quasi-periods of 10 -- 25 s. This may explain the massive jet ejection and the QPOs phenomena observed in SS 433.