Discovery of a 36-minute long-period transient ASKAP J142431.2-612611

Joshua Pritchard; Tara Murphy; Dougal Dobie; Emil Lenc; Akash Anumarlapudi; Manisha Caleb; Sophia Grainger; Natasha Hurley-Walker; David L. Kaplan; Samuel J. McSweeney; Jackson Mitchell-Bolton; Kovi Rose; Rahul Sengar; Ziteng Wang; Jayde Willingham; Andrew Zic

arXiv · 2603.07857

Discovery of a 36-minute long-period transient ASKAP J142431.2-612611

Joshua Pritchard·Tara Murphy·Dougal Dobie·Emil Lenc·Akash Anumarlapudi·Manisha Caleb·Sophia Grainger·Natasha Hurley-Walker·David L. Kaplan·Samuel J. McSweeney·Jackson Mitchell-Bolton·Kovi Rose·Rahul Sengar·Ziteng Wang·Jayde Willingham·Andrew Zic

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Abstract

We report the discovery of a new long-period radio transient, ASKAP J142431.2-612611, with a 36 minute period, identified in the Australian SKA Pathfinder Evolutionary Map of the Universe survey. We detected pulsed emission from ASKAP J142431.2-612611 over a period of eight days during follow-up observations with the Australia Telescope Compact Array, after which the source appears to have switched off. No optical or near-infrared counterpart is detected in archival surveys or in targeted Gemini South FLAMINGOS-2 observations. During its active state, the source exhibits a stable pulse profile with fractional polarisation consistent with 100%, evolving from elliptically to linearly polarised and tracing a well-defined great-circle trajectory on the Poincar\'e sphere. We show that this behaviour is consistent with fully linearly polarised intrinsic emission modified by propagation through a linearly polarised birefringent medium. This discovery expands the known population of long-period transients and highlights the intermittent nature of their activity. We discuss the implications for proposed models of long-period transients and outline future observations needed to constrain the origin of their intermittency and polarisation properties.

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Joshua Pritchard, Tara Murphy, Dougal Dobie, Emil Lenc, Akash Anumarlapudi, Manisha Caleb, Sophia Grainger, Natasha Hurley-Walker, David L. Kaplan, Samuel J. McSweeney, Jackson Mitchell-Bolton, Kovi Rose, Rahul Sengar, Ziteng Wang, Jayde Willingham, Andrew Zic. 2026-03-09. Discovery of a 36-minute long-period transient ASKAP J142431.2-612611. https://arxiv.org/abs/2603.07857

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