Detection of an extremely luminous radio counterpart to the Be/X-ray binary A0538-66
Detection of an extremely luminous radio counterpart to the Be/X-ray binary A0538-66
We present the discovery of radio emission from the Be/X-ray binary A0538 −66 with the Australian Square Kilometre Ar-
ray Pathfinder, and results from a subsequent weekly monitoring campaign with the MeerKAT radio telescope. A0538 −66,
located in the Larg e Mag ellanic Cloud, hosts a neutron star with a short spin period ( P ≈ 69 ms) in a highly eccentric
≈16 . 6 -d orbit . Its rare episodes of super-Eddington accretion, rapid optical and X-ray flares, and other peculiar properties
make it an interesting system among high-mass X-ray binaries. Our MeerKAT data reveal that it is also one of the most
radio-luminous neutron star X-ray binaries observed to date, reaching ≈ 3 × 10 22 erg s −1 Hz −1 (at 1.28 GHz), with radio
emission that appears to be orbitally modulated. We consider several possible mechanisms for the radio emission, and
place A0538 −66 in context by comparing it to similar systems.
astro-ph.HE
Crook-Mansour, Justine
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Fender, Rob
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Andersson, Alex
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Qiu, Hao
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Hughes, Andrew K.
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van den Eijnden, Jakob
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Cowie, Fraser J.
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Motta, Sara
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Monageng, Itumeleng
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Ducci, Lorenzo
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Mereghetti, Sandro
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Mathiba, Andries
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Dobie, Dougal
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Murphy, Tara
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Kaplan, David L.
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Carotenuto, Francesco
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Charles, Phil
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6 April 2026
Crook-Mansour, Justine
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Fender, Rob
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Andersson, Alex
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Qiu, Hao
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Hughes, Andrew K.
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van den Eijnden, Jakob
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Cowie, Fraser J.
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Motta, Sara
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Monageng, Itumeleng
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Ducci, Lorenzo
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Mereghetti, Sandro
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Mathiba, Andries
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Dobie, Dougal
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Murphy, Tara
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Kaplan, David L.
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Carotenuto, Francesco
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Charles, Phil
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Crook-Mansour, Justine, Fender, Rob, Andersson, Alex, Qiu, Hao, Hughes, Andrew K., van den Eijnden, Jakob, Cowie, Fraser J., Motta, Sara, Monageng, Itumeleng, Ducci, Lorenzo, Mereghetti, Sandro, Mathiba, Andries, Dobie, Dougal, Murphy, Tara, Kaplan, David L., Carotenuto, Francesco and Charles, Phil
(2026)
Detection of an extremely luminous radio counterpart to the Be/X-ray binary A0538-66.
Monthly Notices of the Royal Astronomical Society, 548 (1), [stag224].
(doi:10.1093/mnras/stag224).
Abstract
We present the discovery of radio emission from the Be/X-ray binary A0538 −66 with the Australian Square Kilometre Ar-
ray Pathfinder, and results from a subsequent weekly monitoring campaign with the MeerKAT radio telescope. A0538 −66,
located in the Larg e Mag ellanic Cloud, hosts a neutron star with a short spin period ( P ≈ 69 ms) in a highly eccentric
≈16 . 6 -d orbit . Its rare episodes of super-Eddington accretion, rapid optical and X-ray flares, and other peculiar properties
make it an interesting system among high-mass X-ray binaries. Our MeerKAT data reveal that it is also one of the most
radio-luminous neutron star X-ray binaries observed to date, reaching ≈ 3 × 10 22 erg s −1 Hz −1 (at 1.28 GHz), with radio
emission that appears to be orbitally modulated. We consider several possible mechanisms for the radio emission, and
place A0538 −66 in context by comparing it to similar systems.
Text
2601.22741v1
- Author's Original
Available under License Other.
Text
stag224
- Version of Record
More information
Accepted/In Press date: 26 January 2026
e-pub ahead of print date: 3 February 2026
Published date: 6 April 2026
Keywords:
astro-ph.HE
Identifiers
Local EPrints ID: 511747
URI: http://eprints.soton.ac.uk/id/eprint/511747
ISSN: 1365-2966
PURE UUID: ba7cb987-ce13-46cd-806e-51bc1458828e
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Date deposited: 01 Jun 2026 16:33
Last modified: 01 Jun 2026 16:35
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Contributors
Author:
Justine Crook-Mansour
Author:
Rob Fender
Author:
Alex Andersson
Author:
Hao Qiu
Author:
Andrew K. Hughes
Author:
Jakob van den Eijnden
Author:
Fraser J. Cowie
Author:
Sara Motta
Author:
Itumeleng Monageng
Author:
Lorenzo Ducci
Author:
Sandro Mereghetti
Author:
Andries Mathiba
Author:
Dougal Dobie
Author:
Tara Murphy
Author:
David L. Kaplan
Author:
Francesco Carotenuto
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