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arXiv · 2408.15757

A 2.9-hour periodic radio transient with an optical counterpart

N. Hurley-Walker·S. J. McSweeney·A. Bahramian·N. Rea·C. Horvath·S. Buchner·A. Williams·B. W. Meyers·Jay Strader·Elias Aydi·Ryan Urquhart·Laura Chomiuk·T. J. Galvin·F. Coti Zelati·Matthew Bailes
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Abstract

We present a long-period radio transient (GLEAM-X J0704-37) discovered to have an optical counterpart, consistent with a cool main sequence star of spectral type M3. The radio pulsations occur at the longest period yet found, 2.9 hours, and were discovered in archival low-frequency data from the Murchison Widefield Array (MWA). High time resolution observations from MeerKAT show that pulsations from the source display complex microstructure and high linear polarisation, suggesting a pulsar-like emission mechanism occurring due to strong, ordered magnetic fields. The timing residuals, measured over more than a decade, show tentative evidence of a ~6-yr modulation. The high Galactic latitude of the system and the M-dwarf star excludes a magnetar interpretation, suggesting a more likely M-dwarf / white dwarf binary scenario for this system.

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N. Hurley-Walker, S. J. McSweeney, A. Bahramian, N. Rea, C. Horvath, S. Buchner, A. Williams, B. W. Meyers, Jay Strader, Elias Aydi, Ryan Urquhart, Laura Chomiuk, T. J. Galvin, F. Coti Zelati, Matthew Bailes. 2024-08-28. A 2.9-hour periodic radio transient with an optical counterpart. https://arxiv.org/abs/2408.15757

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