A parsec scale X-ray extended structure from the X-ray binary Circinus X-1

TL;DR

This paper reports the detection of parsec-scale X-ray structures associated with the jets of the neutron-star binary Circinus X-1, indicating efficient X-ray outflow production similar to black-hole binaries.

Contribution

First clear detection of extended X-ray structures on parsec scales from Circinus X-1, demonstrating synchrotron emission from neutron-star jets.

Findings

X-ray structures detected on both sides of the jets

X-ray emission consistent with synchrotron origin

Neutron-star binaries can produce efficient X-ray outflows

Abstract

We present the results of the analysis of two Chandra observations of Circinus X-1 performed in 2007, for a total exposure time of ~50 ks. The source was observed with the High Resolution Camera during a long X-ray low-flux state of the source. Cir X-1 is an accreting neutron-star binary system that exhibits ultra-relativistic arcsec-scale radio jets and an extended arcmin-scale radio nebula. Furthermore, a recent paper has shown an X-ray excess on arcmin-scale prominent on the side of the receding radio jet. In our images we clearly detect X-ray structures both on the side of the receding and the approaching radio jet. The X-ray emission is consistent with being from synchrotron origin. Our detection is consistent with neutron-star binaries being as efficient as black-hole binaries in producing X-ray outflows, despite their shallower gravitational potential.