A jet bent by a stellar wind in the black hole X-ray binary Cygnus X-1

TL;DR

This study detects and models jet bending caused by stellar wind in Cygnus X-1, providing the first direct measurement of jet power in a black hole X-ray binary, which aligns with accretion energy estimates and informs feedback models.

Contribution

It presents the first direct measurement of jet power in Cygnus X-1 through modeling wind-induced jet bending using 18 years of radio data.

Findings

Jet power is approximately 2.0 x 10^37 erg/s.

Jet power matches the accretion energy from X-ray luminosity.

Supports assumptions used in galaxy formation and black hole accretion models.

Abstract

Jets provide an important channel for kinetic feedback from accreting black holes into their environment, without which models of the formation of large-scale structure in the universe fail to reproduce the observed properties of galaxies. Hence, an accurate measurement of jet power is critical for understanding black hole growth through accretion and also for quantifying the impact of kinetic feedback. However, the absence of instantaneous jet power measurements has precluded direct comparisons with the accretion luminosity, forcing kinetic feedback models to rely on ad hoc assumptions about how much jet power is released per accreted amount of mass. Here we report the detection of stellar wind-induced bending of the jets in the black hole X-ray binary Cygnus X-1, using 18 years of high-resolution radio imaging. By modeling jet-wind interactions, we determine the current kinetic instantaneous power of the jet to be log$_{10}(L_{\rm jet}/{\rm erg\,s}^{-1}) = 37.3_{-0.2}^{+0.1}$, comparable to the accretion energy determined from its bolometric X-ray luminosity. This result critically places prevailing assumptions about the energetics of black hole powered jets in both galaxy formation simulations, and in scaling models of black hole accretion, on a firm empirical footing.