Parsec-Scale Bipolar X-ray Shocks Produced by Powerful Jets from the Neutron Star Circinus X-1

TL;DR

This paper reports the discovery of large-scale bipolar X-ray jets from the neutron star binary Circinus X-1, revealing insights into jet-ISM interactions, jet power, and emission mechanisms in microquasars.

Contribution

It provides the first detailed observation of multi-scale X-ray jets from Circinus X-1 and constrains jet power and age through spectral analysis.

Findings

Jets have wide opening angles and interact with the interstellar medium.

The jets' spectra suggest cooled synchrotron emission with a cooling age of about 1600 years.

Jet power is constrained between 3e35 and 2e37 erg/s.

Abstract

We report the discovery of multi-scale X-ray jets from the accreting neutron star X-ray binary, Circinus X-1. The bipolar outflows show wide opening angles and are spatially coincident with the radio jets seen in new high-resolution radio images of the region. The morphology of the emission regions suggests that the jets from Circinus X-1 are running into a terminal shock with the interstellar medium, as is seen in powerful radio galaxies. This and other observations indicate that the jets have a wide opening angle, suggesting that the jets are either not very well collimated or precessing. We interpret the spectra from the shocks as cooled synchrotron emission and derive a cooling age of approximately 1600 yr. This allows us to constrain the jet power to be between 3e35 erg/s and 2e37 erg/s, making this one of a few microquasars with a direct measurement of its jet power and the only known microquasar that exhibits stationary large-scale X-ray emission.