A new long period radio transient: Discovery of pulses repeating every 1.16 hours from ASKAP J175534.9-252749.1

TL;DR

This paper reports the discovery of a long period radio transient with a 1.16-hour cycle, exhibiting scattered pulses and variable polarization, suggesting a binary system possibly involving a white dwarf, and emphasizes the need for further observations.

Contribution

The study confirms a new long period transient with a unique pulse pattern and polarization behavior, expanding understanding of such radio sources and their potential binary nature.

Findings

Pulses repeat every 1.16 hours with significant scattering.

Some pulses show measurable polarization with atypical angle behavior.

Historical non-detections suggest intrinsic intermittency on month-long timescales.

Abstract

We report the discovery of several new pulses from the source ASKAP J175534.9-252749.1 (J1755-2527), originally identified from a single 2-min long pulse, confirming it as a long period transient (LPT) with a period of ~1.16 hours. The pulses are significantly scattered, consistent with Galactic electron density models. Two of the new pulses also had measurable polarisation, but unlike the originally detected pulse, the polarisation angle does not behave as expected from the rotating vector model. We interpret historical non-detections of J1755-2527 as an intrinsic intermittency that occurs on month-long timescales, and discuss possible causes. We conjecture that, like some other LPTs with periods >~ 1 hour, J1755-2527 may host a white dwarf in a binary orbit, but note that its period is marginally shorter than the canonical orbital period minimum of cataclysmic variables. Our work highlights the importance of additional observations in establishing the nature of unusual radio-emitting objects.