On the nature of the "radio quiet" black hole binaries

TL;DR

This paper investigates why some black hole binaries are radio-quiet, examining how system parameters and outburst properties influence jet power, and compares these black holes with neutron stars to understand jet production variability.

Contribution

It introduces a jet-toy model linking jet Lorentz factor to accretion luminosity and analyzes factors affecting jet power in radio-quiet black hole binaries.

Findings

Black holes with similar accretion can have diverse jet powers.

A jet-toy model suggests jet speed increases above a certain luminosity.

Radio-quiet black holes differ from neutron stars in jet properties.

Abstract

The accretion/ejection coupling in accreting black hole binaries has been described by empirical relations between the X-ray/radio and X-ray/optical-infrared luminosities. These correlations were initially supposed to be universal. However, recently many sources have been found to produce jets that, given certain accretion-powered luminosities, are fainter than expected from the correlations. This shows that black holes with similar accretion flows can produce a broad range of outflows in power. Here we discuss whether typical parameters of the binary system, as well as the properties of the outburst, produce any effect on the energy output in the jet. We also define a jet-toy model in which the bulk Lorentz factor becomes larger than ~1 above ~0.1% of the Eddington luminosity. We finally compare the "radio quiet" black holes with the neutron stars.