The x-ray corona and jet of cygnus x-1

TL;DR

This paper investigates the properties of the X-ray corona and jet in Cygnus X-1, revealing insights into magnetic field strength, ion temperature, jet velocity, and accretion efficiency, challenging some existing models.

Contribution

It provides new observational constraints on the magnetic field, ion temperature, and jet dynamics in Cygnus X-1, refining our understanding of accretion and jet physics.

Findings

Coronal magnetic field may be below equipartition with radiation.

Ion temperature in the corona is lower than ADAF model predictions.

Jet velocity is at least mildly relativistic, with high accretion efficiency.

Abstract

Evidence is presented indicating that in the hard state of Cygnus X-1, the coronal mag- netic field might be below equipartition with radiation (suggesting that the corona is not powered by magnetic field dissipation) and that the ion temperature in the corona is significantly lower than what predicted by ADAF like models. It is also shown that the current estimates of the jet power set interesting contraints on the jet velocity (which is at least mildly relativistic), the accretion efficiency (which is large in both spectral states), and the nature of the X-ray emitting region (which is unlikely to be the jet).