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

报告人：周霞 研究员（中国科学院新疆天文台）

报告摘要：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, and ASKAP J193505.1+214841.0. 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.

报告人简介：周霞，现任中国科学院新疆天文台台长，研究员，主要从事脉冲星及中子星物理研究，发表相关SCI论文60余篇。主持自然科学基金面上项目，参与多项重点研发及自然科学基金重点项目，获自治区自然科学基金杰青项目、新疆战略人才培养计划一流科技领军人才、中国科学院区域青年学者等项目支持。

时间：2026年5月7日16点

地点：中国科学院紫金山天文台仙林园区3-402会议室

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