Formation of recollimation shocks in jets of high-mass X-ray binaries

TL;DR

This paper investigates the conditions under which recollimation shocks form in jets of high-mass X-ray binaries, identifying a critical jet power threshold and validating predictions with 3-D simulations.

Contribution

It introduces a critical jet power criterion for recollimation shock formation and confirms it through numerical simulations, applying findings to specific X-ray binaries.

Findings

Existence of a critical jet power for shock formation

Location of shocks below the critical power

Surface shocks above the critical power are limited in volume

Abstract

We study conditions for formation of recollimation shocks in jets interacting with stellar winds in high-mass X-ray binaries. We show the existence of a critical jet power, dependent on the wind rate and velocity and the jet velocity, above which a recollimation shock is not formed. For jet powers below critical, we derive the location of the shock. We show that surface shocks may still exist above the critical power, but only occupy a small volume of the jet and do not significantly alter the jet opening angle. We test these prediction by 3-D numerical simulations, which confirm the existence and the value of the critical power. We apply our results to Cyg X-1 and Cyg X-3.