发表机构
Sweet Briar College; Curtin University; National Radio Astronomy Observatory; U.S. Naval Research Laboratory（斯威特布里尔学院; 科廷大学; 美国国家射电天文台; 美国海军研究实验室）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究在MeerKAT和ASKAP数据中发现周期62.2分钟的长周期暂现源LPT J1555$-$5631，其双脉冲偏振特性表明其为近正交自转体，辐射源于复杂磁层，支持相干辐射机制。
AI 中文摘要
我们报告在MeerKAT和ASKAP巡天数据中偶然发现了J155543.7$-$563102（以下简称LPT J1555$-$5631），其周期为62.2分钟。该源在2022年5月一个15小时的活跃窗口期间发射了明亮的（10-30 mJy）、陡谱（$\alpha\sim-1.5$）、高度偏振的射电脉冲，在此前后约5年内未探测到其他宁静或脉冲发射。平均光变曲线每个周期显示出两个交替脉冲。主脉冲（MP）和中间脉冲（IP）相隔$\Delta\phi=165.4^\circ$，振幅相似，但偏振特性不同：较宽的主脉冲（占空比3.9%）具有部分线偏振和圆偏振，且偏振位置角恒定；而较窄的中间脉冲（占空比1.1%）几乎100%为圆偏振。我们将LPT J1555$-$5631归类为近正交自转体，其一次自转期间两个磁极的辐射均可见，且磁轴与自转轴几乎垂直。与对跖点相隔14.6$^\circ$的偏差以及几乎恒定的偏振位置角表明，该辐射并非源于普通脉冲星的标准偶极极冠几何结构，而是起源于更宽广、更复杂的磁层。LPT J1555$-$5631的观测特性可由扩展辐射区域来解释，并倾向于支持相干辐射机制，如电子回旋脉泽不稳定性，尽管这些特性并不能唯一确定其前身星或辐射物理过程。如果这些推断更广泛地适用于长周期暂现源族群，它们可以解释为何其波束宽度与自转周期脱钩、平坦偏振位置角的普遍性，并可能支持正交自转体出现率较高的情况。
英文摘要
We report the serendipitous discovery of J155543.7$-$563102 (hereafter LPT J1555$-$5631) with a period of 62.2 min in MeerKAT and ASKAP survey data. The source emitted bright (10-30 mJy), steep-spectrum ($α\sim-1.5$), highly polarized radio pulses during a 15-hr active window in May 2022, with no other quiescent or pulsed emission detected before or after over $\sim5$ years. The mean light curve exhibits two alternating pulses per cycle. A main pulse (MP) and an interpulse (IP) separated by $Δϕ=165.4^\circ$ with similar amplitudes, but different polarization properties: the wider MP (3.9%) is partially linearly and circularly polarized and shows a constant polarization position angle, while the narrow IP (1.1%) is $\sim$100% circularly polarized. We classify LPT J1555$-$5631 as a near-orthogonal rotator, for which emission from both magnetic poles is visible during one rotation and the magnetic and rotation axes are almost perpendicular. The 14.6$^\circ$ deviation from an antipodal separation and the nearly constant polarization position angle suggest that the emission does not arise from the standard dipolar polar-cap geometry of ordinary pulsars, but instead originates within a broader, more complex magnetosphere. The observed properties of LPT J1555$-$5631 can be accommodated by extended emission regions, and favor coherent emission mechanisms such as the electron cyclotron maser instability, although they do not uniquely determine the progenitor or emission physics. If these inferences apply more broadly to the LPT population, they could account for why their beam widths are decoupled from rotation periods, the prevalence of flat polarization position angles, and may favor an elevated incidence of orthogonal rotators.
Comments23 pages, 11 figures. Accepted for publication in The Astrophysical Journal
