AI 中文总结
该研究针对长周期射电瞬变源，结合周期约束与伴星探测结果，提出将其分为孤立致密天体和双星系统两类的分类框架，并给出对应辐射机制与观测判据。
AI 中文摘要
长周期射电瞬变源（LPRTs）是一类快速增长的相干射电源，周期范围从数分钟到数小时，其中心引擎和辐射机制仍不清楚。受多个LPRTs中红矮星（RD）伴星的探测结果，以及洛希极限和质量转移极限给出的通用周期约束的启发，我们认为LPRTs可自然分为两大类：周期较短的源可能是孤立致密天体，周期较长的源则是大概率为分离态的双星系统中的致密天体。对于孤立天体，我们发现孤立白矮星（WD）通常难以维持对产生和相干射电辐射，除非其表面温度极高；而慢旋转中子星（NS）可通过逆康普顿驱动的对级联勉强保持活跃。对于双星系统，当白矮星/中子星的磁场主导伴星表面磁场时，异步白矮星/中子星+红矮星系统可通过单极感应产生相干射电辐射，辐射机制为相对论电子回旋脉泽辐射；在更大的间距下，系统进入磁层相互作用区域，可能由磁重联提供能量。明亮的X射线对应体更倾向于磁星相关系统，而白矮星相关通道预计会产生未被探测到的X射线辐射。我们提出了一个诊断流程图，利用观测标准对LPRTs进行分类并确定其中心引擎，这些标准构成了一个基于物理的LPRTs分类框架。
英文摘要
Long-period radio transients (LPRTs) are a rapidly growing class of coherent radio sources with periods ranging from minutes to hours, whose central engines and emission mechanisms remain unclear. Motivated by the detection of red dwarf (RD) companions in several LPRTs and by generic period constraints from the Roche limit and the mass transfer limit, we argue that LPRTs naturally separate into two broad classes: shorter-period sources that are likely isolated compact objects and longer-period sources that are compact objects in binary systems that are likely detached. For isolated objects, we find that isolated white dwarfs (WDs) generally have difficulty sustaining pair production and coherent radio emission unless the surface temperature is extremely high, while slow rotating neutron stars (NSs) can remain marginally active through inverse-Compton-driven pair cascades. For binary systems, asynchronous WD / NS + RD systems can power coherent radio emission through unipolar induction when the WD / NS magnetic field dominates the companion surface field, with relativistic electron cyclotron maser emission as the radiation mechanism, while at larger separations the system enters the magnetospheric interaction regime, possibly powered by magnetic reconnection. Bright X-ray counterparts favor magnetar-related systems and undetected X-ray emission is expected from WD-related channels. We propose a diagnostic flow chart that uses observational criteria to classify LPRTs and identify their central engines. These criteria lead to a physically motivated classification framework for LPRTs.
Comments32 pages, 12 figures, 2 tables
