Disk-jet-wind coupling from stellar mass to supermassive black holes

TL;DR

This paper reviews how accretion processes, spectral transitions, and wind and jet properties in black holes of all masses are interconnected, highlighting the role of accretion rate and spin in shaping observable phenomena.

Contribution

It presents a unified framework linking spectral states, winds, and jets in stellar and supermassive black holes based on accretion rate and spin considerations.

Findings

Spectral transition at 0
% Eddington ratio affects wind properties.

Hot flow connects to radio jets in both stellar and supermassive black holes.

Radio loudness correlates with higher black hole spin.

Abstract

Black holes are the simplest possible objects, characterised by only mass and spin. We see them via accretion, so there is one more fundamental parameter which is the mass accretion rate. Here I will review how the data from both stellar and supermassive black holes can be fit into a framework where there is a major spectral transition at $\dot{m}=L/L_{\rm Edd}\sim 0.01$ where the optically thick disc is replaced by a hot flow. This dramatic spectral change also affects the expected properties of thermal and radiatively powered winds, matching the overall properties of winds seen in new XRISM data from the stellar mass binaries, though there can also be additional UV and dust driven winds in supermassive black holes. The radio data in stellar and supermassive black holes are clear that the hot flow (not the disc) connects to the radio jet, and the radio-X-ray 'fundamental plane' can be qualitatively understood if the radio quiet AGN and stellar mass black holes have low to moderate spins, with the jet power set as a constant fraction of the accretion power. A small fraction of AGN (radio loud) instead have much higher (factor $100-1000\times$) radio-to-X-ray ratio at the same black hole mass and mass accretion rates. I speculate that these have higher jet power due to high black hole spin. I review the multiple issues still remaining in this picture, most of which are connected to the geometry and nature of the X-ray corona, and the conflicting constraints on this which come from reflection spectroscopy and polarimetry.