Explaining the 'outliers' track in Black Hole X-ray Binaries with the BZ-jet and inner-disk coupling

TL;DR

This paper explores how the BZ-jet mechanism and inner-disk coupling explain the outliers in radio/X-ray correlations in two black hole X-ray binaries, highlighting differences in accretion states and the MAD condition.

Contribution

It demonstrates that BZ-jet and inner-disk coupling can account for outliers in radio/X-ray correlations, and discusses the accretion states and phase transitions in BHXBs.

Findings

BZ-jet and inner-disk coupling explain outliers in two BHXBs.

H1743-322 likely in MAD state; MAXI J1348-630 less so.

Phase transition occurs around L_X/L_Edd ~ 10^-3.

Abstract

In this paper, we investigate the black hole (BH) spin contribution to jet power, especially for the magnetic arrested disk (MAD), where only inner accretion disk luminosity is closely coupled with the spin-jet power, and try to explain the `outliers' track of the radio $L_{\rm R}$ to X-ray luminosity $L_{\rm X}$ in two black hole X-ray binaries (BHXBs). Our results suggest that the BZ-jet and the inner-disk coupling could account for the `outliers' track of the radio/X-ray correlation in two BHXBs, H1743-322 and MAXI J1348-630. Although the accretion disk of H1743-322 in the outburst could be in the MAD state, there is a lower probability that MAXI J1348-630 is in the MAD state due to its low jet production efficiency. The difference in the inner-disk bolometric luminosity ratio of the two sources implies that these two BHXBs are in different inner-disk accretion states. We further investigate the phase-changing regime of MAXI J1348-630 and find that there is a phase transition around $L_{\rm X}/L_{\rm Edd}\sim 10^{-3}$. The assumption of sub-MAD is discussed as well.