A disk-corona model for low/hard state of black hole X-ray binaries

TL;DR

This paper proposes a disk-corona model for the low/hard state of black hole X-ray binaries, integrating magnetic field configurations from BZ and BP processes to explain jet launching and state transitions.

Contribution

It introduces a combined BZ and BP magnetic field model for BHXB jets, emphasizing the role of corona currents and magnetic configuration in state transitions.

Findings

Model successfully fits LH states of several BHXBs.

Highlights the importance of corona currents in jet launching.

Suggests magnetic field configuration as a second parameter for state transitions.

Abstract

A disk-corona model for fitting low/hard (LH) state of associated steady jet of black hole X-ray binaries (BHXBs) is proposed based on the large-scale magnetic field configuration of the coexistence of the Blandford-Znajek (BZ) and Blandford-Payne (BP) processes,where the magnetic field configuration for the BP process is determined by the requirement of energy conversion from Poynting energy flux into kinetic energy flux in the jet. It is found that corona current is crucial to guarantee the consistency of the jet launching from accretion disk. The relative importance of the BZ to BP processes in powering jets from black hole accretion disk is discussed, and the LH state of several BHXBs is fitted based on our model.In addition, we suggest that magnetic field configuration could be regarded as the second parameter for governing the state transition of BHXBs.