Discovery of a large and bright bow shock nebula associated with low mass X-ray binary SAX J1712.6-3739

TL;DR

This paper reports the discovery of a large, bright bow shock nebula associated with a low-mass X-ray binary, providing a unique opportunity to study accretion and jet energetics in such systems.

Contribution

It presents the first observation of a bow shock nebula linked to a low-mass X-ray binary, expanding understanding of nebulae associated with these sources.

Findings

Discovery of a bow shock nebula associated with SAX J1712.6-3739

Identification of the optical counterpart as a highly extincted neutron star LMXB

Proposed models for nebula formation and observational tests

Abstract

In a multiwavelength program dedicated to identifying optical counterparts of faint persistent X-ray sources in the Galactic Bulge, we find an accurate X-ray position of SAX J1712.6-3739 through Chandra observations, and discover its faint optical counterpart using our data from EFOSC2 on the ESO 3.6m telescope. We find this source to be a highly extincted neutron star LMXB with blue optical colours. We serendipitously discover a relatively bright and large bow shock shaped nebula in our deep narrowband H alpha imaging, most likely associated with the X-ray binary. A nebula like this has never been observed before in association with a LMXB, and as such provides a unique laboratory to study the energetics of accretion and jets. We put forward different models to explain the possible ways the LMXB may form this nebulosity, and outline how they can be confirmed observationally.