白矮星脉冲星：一类新兴的致密双星
White Dwarf Pulsars: an emerging class of compact binaries
浏览论文内容
中文总结 AI 辅助
本文综述了以AR Scorpii为代表的白矮星脉冲星新天体类别，介绍其发现、磁层电子加速产生同步辐射的机制、高偏振特性，并指出其可能代表双星演化的短暂过渡阶段。
中文摘要 AI 辅助
我总结了正在扩展的白矮星脉冲星这一类天体，其原型AR Scorpii直到2016年才被发现。在本次会议召开时，又发现了两个此类系统（eRASSU J191213.9-441044和SDSS J230641.47+244055.8）。这些系统被认为是分离（或几乎分离）的白矮星-红矮星双星，其中白矮星的磁场与M星的日冕相互作用，导致电子在磁层中被捕获并加速到相对论速度。这在整个电磁波谱上产生了非热同步辐射。第一个被发现且最亮的系统AR Sco（本文重点研究对象）显示出白矮星的自转减慢，这与强磁场白矮星中的磁偶极辐射一致。已获得偏振测量的两个系统（AR Sco和eRASSU J191213.9-441044）的偏振特性显示出自转调制的偏振，主要是线偏振，在AR Sco中偏振度显著达到40%。此外，Stokes Q和U参数的变化方式与蟹状星云脉冲星的光学偏振相同，与旋转磁偶极子一致。这些系统引人入胜之处在于，每个系统似乎都表现出不同的行为（例如脉冲轮廓和光变曲线特性），这大概主要是由于不同的观测视角。最近有人提出，这些系统代表了双星演化的一个短暂阶段，连接了异步旋转的中间激变变星和同步激变变星。
英文摘要
I summarise the expanding class of white dwarf pulsars for which the prototype, AR Scorpii, was only discovered in 2016. At the time of this meeting, two further systems had been found (eRASSU J191213.9-441044 and SDSS J230641.47+244055.8). These are thought to be detached (or nearly detached) white-dwarf--red-dwarf binaries, where the white dwarf's magnetic field interacts with the M-star's corona, resulting in the capture and acceleration of electrons to relativistic velocities in the magnetosphere. This gives rise to non-thermal synchrotron emission across the electromagnetic spectrum. The first discovered, and brightest, system, AR Sco (which is the focus of this paper), shows a white dwarf spin-down consistent with magnetic dipole emission in a strongly magnetic white dwarf. The polarisation properties of the two systems for which polarimetry has been obtained (AR Sco and eRASSU J191213.9-441044) show spin-modulated polarisation, primarily linear, which remarkably reaches 40% in AR Sco. Furthermore, the Stokes Q and U parameters vary in the same manner as the optical polarisation of the Crab pulsar, consistent with a rotating magnetic dipole. These systems are intriguing in that each one seems to show different behaviours (e.g. pulse profiles and light-curve properties), presumably mainly due to different viewing aspect angles. It has recently been postulated that these systems represent a short-lived phase of binary evolution linking asynchronously rotating intermediate polars and synchronous polars.
