Dark jets in the soft X-ray state of black hole binaries?

TL;DR

This paper explores the possibility that black hole X-ray binaries may host undetectable 'dark' jets during their soft states, challenging the traditional view that jets are quenched in this phase.

Contribution

The study demonstrates through modeling that powerful dark jets could persist in the soft state without contradicting current observational upper limits.

Findings

Predicted radio emission aligns with current upper limits.

Dark jets may persist in the soft state without significant kinetic power change.

Challenges the assumption that jets are fully quenched in the soft state.

Abstract

X-ray binary observations led to the interpretation that powerful compact jets, produced in the hard state, are quenched when the source transitions to its soft state. The aim of this paper is to discuss the possibility that a powerful dark jet is still present in the soft state. Using the black hole X-ray binaries GX339-4 and H1743-322 as test cases, we feed observed X-ray power density spectra in the soft state of these two sources to an internal shock jet model. Remarkably, the predicted radio emission is consistent with current upper-limits. Our results show that, for these two sources, a compact dark jet could persist in the soft state with no major modification of its kinetic power compared to the hard state.