Parkes observations for project P1325 semester 2025APRS_02

We request 15 hours of observing time with the Parkes UWL receiver (700-4000 MHz) to investigate frequency-dependent eclipsing in three spider millisecond pulsars (MSPs): one redback and two black widows. Spider MSPs commonly exhibit frequency-dependent eclipsing, which provides insights into their dense, magnetized plasma environments. We propose to use the Parkes telescope with the UWL receiver in full polar mode to investigate key properties of three spider MSPs, focusing on their eclipse mechanisms and polarization characteristics. Our goals include modeling the eclipse phase spectra using wideband observations to examine the transition from optically thick to thin regimes and exploring the underlying eclipse mechanisms. Additionally, we aim to study the polarization properties of these MSPs, which remain unexplored around 2 GHz, and also to investigate high-frequency eclipses similar to those observed in systems like J1908+2105. Such eclipses suggest the presence of dense and magnetized plasma environments, enabling more precise constraints on parameters like electron column density and magnetic field strengths. Furthermore, we plan to probe magnetic fields by observing potential changes in rotation measure (RM) at eclipse ingress and egress.我们申请使用帕克斯UWL接收机（Parkes UWL receiver，工作频段700–4000 MHz）获取15小时观测时间，以研究三颗蜘蛛状毫秒脉冲星（spider millisecond pulsars, MSPs）的频率依赖型食现象：其中1颗为红背蜘蛛脉冲星（redback），另外2颗为黑寡妇蜘蛛脉冲星（black widow）。蜘蛛状毫秒脉冲星普遍存在频率依赖型食现象，该现象可为解析其致密磁化等离子体环境提供关键依据。我们拟采用搭载UWL接收机的帕克斯望远镜，以全偏振模式开展观测，旨在探究三颗蜘蛛状毫秒脉冲星的核心特性，重点聚焦其食机制与偏振特征。本次观测的目标包括：通过宽带观测构建食相光谱模型，以检验等离子体从光学厚到光学薄区域的过渡过程，并深入探究其背后的食形成机制；此外，我们还将研究这些毫秒脉冲星的偏振特性——目前在约2 GHz频段尚无相关探测记录——并搜寻类似J1908+2105等系统中已观测到的高频食现象。这类食现象表明目标系统存在致密磁化等离子体环境，借此可对电子柱密度、磁场强度等参数实现更为精准的约束。进一步而言，我们计划通过观测食相始入与始出阶段的旋转测量量（rotation measure, RM）变化，对目标磁场展开探测。