SMSS J130522.47-293113.0: a high-latitude stellar X-ray source with pc-scale outflow relics?

TL;DR

This paper reports the discovery of an unusual stellar system with a possible nova-like CV and pc-scale outflow relics, characterized by variable emission lines, optical fluctuations, and symmetrically placed optical/IR blobs.

Contribution

It presents the identification of a stellar system with unique optical, X-ray, and morphological features, suggesting relics of a collimated outflow from a nova-like CV.

Findings

System has variable emission lines and optical fluctuations.

Detected two symmetric optical/IR blobs as outflow relics.

System is a weak X-ray source with no radio detection.

Abstract

We report the discovery of an unusual stellar system, SMSS J130522.47-293113.0. The optical spectrum is dominated by a blue continuum together with emission lines of hydrogen, neutral and ionized helium, and the N III, C III blend at around 4640-4650 Angstrom. The emission line profiles vary in strength and position on timescales as short as 1 day, while optical photometry reveals fluctuations of as much as ~0.2 mag in g on timescales as short as 10-15 min. The system is a weak X-ray source (f_{0.3-10} = (1.2 +/- 0.1) x 10^{-13} ergs cm^{-2} s^{-1} in the 0.3-10 keV band) but is not detected at radio wavelengths (3-sigma upper limit of 50 microJy at 5.5 GHz). The most intriguing property of the system, however, is the existence of two "blobs", a few arcsec in size, that are symmetrically located 3.8 arcmin (2.2 pc for our preferred system distance of ~2 kpc) each side of the central object. The blobs are detected in optical and near-IR broadband images but do not show any excess emission in Halpha images. We discuss the interpretation of the system, suggesting that the central object is most likely a nova-like CV, and that the blobs are relics of a pc-scale accretion-powered collimated outflow.