长周期射电暂现源ASKAP/DART J1832-0911的双星性质证据
Evidence for the binary nature of the long-period radio transient ASKAP/DART J1832-0911
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- International Centre for Radio Astronomy Research, Curtin University（国际射电天文研究中心，科廷大学）
- Australia Telescope National Facility, CSIRO（澳大利亚望远镜国家设施，联邦科学与工业研究组织）
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中文总结 AI 辅助
本研究通过两年射电数据分析，提出最亮长周期暂现源ASKAP/DART J1832-0911可能为超紧凑异步极化双星系统，其脉冲形态、法拉第旋转量及X射线辐射变化均支持该模型，并给出了可检验的预测。
中文摘要 AI 辅助
长周期暂现源是一类以分钟至小时为周期重复辐射的周期性脉冲射电源。近期，越来越多的此类源被识别为双星系统，具体而言是带有低质量主序伴星的白矮星系统。在本工作中，我们利用两年的射电数据分析了迄今发现的最亮长周期暂现源ASKAP/DART J1832-0911，并提出它也可能是一个白矮星系统，尽管其轨道远比前述系统更为紧凑。其脉冲由准周期分量组成，这些分量在数天至数月的时间尺度上以系统性的方式演化。该源具有高度线偏振或椭圆偏振，其亮度使得我们能够以极高信噪比测量时间分辨的法拉第旋转量，并发现该旋转量随脉冲相位而变化。线偏振位置角、圆偏振分数和谱指数也以不同于脉冲星和磁星典型特征的方式系统性变化。我们表明，一个超紧凑异步极化体（AM型激变变星）可以解释ASKAP/DART J1832-0911的大部分现象学特征，特别是脉冲形态的演化、旋转量变化以及周期性X射线辐射，尽管我们无法确凿地证明其双星性质。然而，我们的模型做出了可检验的预测。
英文摘要
Long-period transients are a class of periodic pulsed radio source repeating on the minute to hour timescale. Recently, an increasing number of them are being identified as binary systems, specifically white dwarfs with low-mass main-sequence companions. In this work we analyse the most luminous long-period transient discovered to date, ASKAP/DART J1832-0911, with two years of radio data, and propose that it, too, may be a white dwarf system, although in a far more compact orbit than the aforementioned. The pulses are composed of quasi-periodic components which evolve in a systematic way over days and months. The source is highly linearly or elliptically polarised and its brightness enabled very high signal-to-noise measurement of the time-resolved Faraday rotation measure, which was found to vary across pulse phase. The linear polarisation position angle, circular polarised fraction, and spectral index also varied systematically in ways not typical of pulsars and magnetars. We show that an ultra-compact asynchronous polar explains much of the phenomenology of ASKAP/DART J1832-0911, in particular the evolution of the pulse morphology, rotation measure variation, and periodic X-ray emission, although we cannot conclusively prove a binary nature. However, our model makes testable predictions.
