A sample of short-lived Galactic radio transients from ASKAP VAST

TL;DR

This paper reports the discovery of six new Galactic radio transients from ASKAP VAST, suggesting they may be linked to white dwarf binaries and highlighting the potential of wide-field radio surveys to uncover new astrophysical phenomena.

Contribution

The study identifies six new Galactic radio transients and proposes their classification, linking them to white dwarf binaries and expanding understanding of Galactic radio transient populations.

Findings

Six new Galactic radio transients discovered along the Galactic plane.

Short-term transients may be related to wide-orbit white dwarf binaries.

Long-term transients could be dust-obscured outbursts from white dwarf binaries.

Abstract

Galactic radio transients (GRTs) are mysterious short-lived (~days to months) radio transients that are quiet at all other wavelengths. Until now, roughly half a dozen such sources have been reported, predominantly towards the Galactic center. However, no unifying properties have been identified among these, leaving their nature, emission mechanism, and even classification poorly understood. Due to the lack of periodic and uniform radio observations over wide areas of the Galactic plane until now, the sample size of such transients remained limited. Here, we use radio observations from the Australian SKA Pathfinder's Variables and Slow Transients survey to discover six new radio transients along the Galactic plane that resemble GRTs. Detailed investigation of archival data suggests that these sources may be divided into two classes: sources that exhibit sporadic, pulse-like (minutes) radio emission, and sources that exhibit long-term (weeks) flaring-type radio emission. For the short-time variable sources, we draw similarities between optically bright long-period radio transients and our sample to propose wide-orbit (~days) white dwarf binaries as underlying sources. For sources that show long-term outbursts, we draw comparisons between dust-obscured outbursts from WD binaries and our sample. These results could imply that the ongoing wide-field radio surveys are uncovering radio emission from sub-populations of WD binaries that were previously unexplored.