Nature of Ultralong Period Radio Transients: Could They Be Strange Dwarf Pulsars?

Ultralong period radio transients (ULPTs), with periods of thousands of seconds, challenge conventional pulsar models. We propose that these isolated sources are strange dwarf (SD) pulsars—compact objects with a strange quark matter core surrounded by a normal matter crust. We develop a theoretical...

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Main Authors: Xia Zhou, Abdusattar Kurban, Wen-Tong Liu, Na Wang, Ya-Jing Yuan
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:The Astrophysical Journal
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Online Access:https://doi.org/10.3847/1538-4357/add268
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author Xia Zhou
Abdusattar Kurban
Wen-Tong Liu
Na Wang
Ya-Jing Yuan
author_facet Xia Zhou
Abdusattar Kurban
Wen-Tong Liu
Na Wang
Ya-Jing Yuan
author_sort Xia Zhou
collection DOAJ
description Ultralong period radio transients (ULPTs), with periods of thousands of seconds, challenge conventional pulsar models. We propose that these isolated sources are strange dwarf (SD) pulsars—compact objects with a strange quark matter core surrounded by a normal matter crust. We develop a theoretical framework for SD pulsars and apply it to four known isolated ULPTs: GLEAM-X J162759.5–523504.3, GPM J1839–10, ASKAP J1832–0911 (DART J1832–0911), and ASKAP J193505.1+214841.0 (ASKAP J1935+2148). Our analysis shows that SD pulsars naturally explain both the ultralong periods and coherent radio emission of these sources, which occupy a distinctive region in the magnetic field–period diagram. We find that these objects have surface magnetic fields ranging from 10 ^6 to 10 ^10 G, with a consistent lower bound near 10 ^6 G that suggests a fundamental threshold for pair production in these magnetospheres. Their radio emission efficiencies ( η _rad,rot  ≈ 10 ^−4 –10 ^−2 ) align with those of normal pulsars despite their extreme periods. ASKAP J1935+2148 represents a boundary case, positioned below the theoretical death line but still radio active, offering crucial insights into emission mechanisms at extreme periods. The observed X-ray properties of ASKAP J1832–0911, including its two-component spectrum and synchronous X-ray/radio variability, strongly support the SD pulsar model. This framework provides a unified explanation for ULPTs and has significant implications for understanding exotic dense matter in compact objects.
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spelling doaj-art-db9cc2b861744ec2b29a9df7df4b79662025-08-20T03:10:23ZengIOP PublishingThe Astrophysical Journal1538-43572025-01-0198619810.3847/1538-4357/add268Nature of Ultralong Period Radio Transients: Could They Be Strange Dwarf Pulsars?Xia Zhou0https://orcid.org/0000-0003-4686-5977Abdusattar Kurban1https://orcid.org/0000-0002-2162-0378Wen-Tong Liu2Na Wang3https://orcid.org/0000-0002-9786-8548Ya-Jing Yuan4Xinjiang Astronomical Observatory, Chinese Academy of Sciences , Urumqi 830011, People’s Republic of China ; zhouxia@xao.ac.cn; State Key Laboratory of Radio Astronomy and Technology , Beijing 100101, People’s Republic of China; Xinjiang Key Laboratory of Radio Astrophysics , 150 Science1 Street, Urumqi 830011, People’s Republic of ChinaXinjiang Astronomical Observatory, Chinese Academy of Sciences , Urumqi 830011, People’s Republic of China ; zhouxia@xao.ac.cn; Xinjiang Key Laboratory of Radio Astrophysics , 150 Science1 Street, Urumqi 830011, People’s Republic of ChinaXinjiang Astronomical Observatory, Chinese Academy of Sciences , Urumqi 830011, People’s Republic of China ; zhouxia@xao.ac.cn; University of Chinese Academy of Sciences , 19A Yuquan Road, Beijing 100049, People’s Republic of ChinaXinjiang Astronomical Observatory, Chinese Academy of Sciences , Urumqi 830011, People’s Republic of China ; zhouxia@xao.ac.cn; State Key Laboratory of Radio Astronomy and Technology , Beijing 100101, People’s Republic of China; Xinjiang Key Laboratory of Radio Astrophysics , 150 Science1 Street, Urumqi 830011, People’s Republic of ChinaXinjiang Astronomical Observatory, Chinese Academy of Sciences , Urumqi 830011, People’s Republic of China ; zhouxia@xao.ac.cn; University of Chinese Academy of Sciences , 19A Yuquan Road, Beijing 100049, People’s Republic of ChinaUltralong period radio transients (ULPTs), with periods of thousands of seconds, challenge conventional pulsar models. We propose that these isolated sources are strange dwarf (SD) pulsars—compact objects with a strange quark matter core surrounded by a normal matter crust. We develop a theoretical framework for SD pulsars and apply it to four known isolated ULPTs: GLEAM-X J162759.5–523504.3, GPM J1839–10, ASKAP J1832–0911 (DART J1832–0911), and ASKAP J193505.1+214841.0 (ASKAP J1935+2148). Our analysis shows that SD pulsars naturally explain both the ultralong periods and coherent radio emission of these sources, which occupy a distinctive region in the magnetic field–period diagram. We find that these objects have surface magnetic fields ranging from 10 ^6 to 10 ^10 G, with a consistent lower bound near 10 ^6 G that suggests a fundamental threshold for pair production in these magnetospheres. Their radio emission efficiencies ( η _rad,rot  ≈ 10 ^−4 –10 ^−2 ) align with those of normal pulsars despite their extreme periods. ASKAP J1935+2148 represents a boundary case, positioned below the theoretical death line but still radio active, offering crucial insights into emission mechanisms at extreme periods. The observed X-ray properties of ASKAP J1832–0911, including its two-component spectrum and synchronous X-ray/radio variability, strongly support the SD pulsar model. This framework provides a unified explanation for ULPTs and has significant implications for understanding exotic dense matter in compact objects.https://doi.org/10.3847/1538-4357/add268Compact objectsPulsarsNeutron starsRadio transient sources
spellingShingle Xia Zhou
Abdusattar Kurban
Wen-Tong Liu
Na Wang
Ya-Jing Yuan
Nature of Ultralong Period Radio Transients: Could They Be Strange Dwarf Pulsars?
The Astrophysical Journal
Compact objects
Pulsars
Neutron stars
Radio transient sources
title Nature of Ultralong Period Radio Transients: Could They Be Strange Dwarf Pulsars?
title_full Nature of Ultralong Period Radio Transients: Could They Be Strange Dwarf Pulsars?
title_fullStr Nature of Ultralong Period Radio Transients: Could They Be Strange Dwarf Pulsars?
title_full_unstemmed Nature of Ultralong Period Radio Transients: Could They Be Strange Dwarf Pulsars?
title_short Nature of Ultralong Period Radio Transients: Could They Be Strange Dwarf Pulsars?
title_sort nature of ultralong period radio transients could they be strange dwarf pulsars
topic Compact objects
Pulsars
Neutron stars
Radio transient sources
url https://doi.org/10.3847/1538-4357/add268
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