Parkes observations for project P1295 semester 2023OCTS_05

We propose observing time with the Parkes telescope to investigate four ``spider" millisecond pulsars (MSPs), PSR J1048+2339 (a redback spider), PSR J1908+2105 (an MSP that occupies a region of parameter space between black widows and redbacks), PSR J2052+1219 and PSR J2256-1024 (black widow spiders). Spider MSPs are commonly seen to exhibit frequency-dependent eclipsing. Observations with wide bandwidth telescopes like Parkes UWL (700-4000 MHz) will be extremely useful to study the eclipse mechanisms in these systems. Eclipse properties of spider MSPs are hitherto unexplored at the frequency regime available with the Parkes UWL receiver. We propose to investigate a sample of 4 MSPs mentioned above (for which polarization has not been studied) with the Parkes telescope using the UWL receiver in full polar mode, which will be addressed with this proposal. One of the aims is to model the eclipse phase spectra using wideband observations of these pulsars in an optically thick-to-thin transitioning regime (optical depth nearly 1), to explore the eclipse mechanism.\n Observing the possible changes in rotation measure (RM) at eclipse ingress and egress will allow us to probe the magnetic field in the eclipse boundaries. \n We request to cover nearly one full orbit for each of these MSPs. Thus we propose 23 hours of observing time including time for setup and calibration in each epoch with the Parkes UWL receiver for the investigation of the eclipse mechanism as well as the polarization, profile evolution, and spectra of four spider MSPs.

本提案申请使用帕克斯（Parkes）望远镜观测时间，以研究4颗"蜘蛛类"毫秒脉冲星（millisecond pulsars, MSPs）：PSR J1048+2339（红背蜘蛛类脉冲星）、PSR J1908+2105（一颗处于黑寡妇与红背类脉冲星参数空间交界区域的毫秒脉冲星）、PSR J2052+1219与PSR J2256-1024（黑寡妇蜘蛛类脉冲星）。
蜘蛛类毫秒脉冲星通常表现出频率依赖的食掩现象。诸如帕克斯UWL接收机（700-4000 MHz）这类宽带望远镜的观测，将为研究此类系统的食掩机制提供极大助力。目前，针对蜘蛛类毫秒脉冲星的食掩特性，尚未在帕克斯UWL接收机覆盖的频段范围内开展过相关研究。
本提案拟利用帕克斯望远镜搭载UWL接收机的全极化模式，对上述4颗尚未开展极化研究的毫秒脉冲星进行观测研究。其中一项核心目标为：在光厚-光薄过渡区域（光学深度约为1）中，通过对这些脉冲星的宽带观测构建食掩相位谱模型，以探索食掩机制。
通过观测食掩进入与退出阶段旋转测量（rotation measure, RM）的潜在变化，我们将能够探测食掩边界处的磁场。
我们计划对每颗目标毫秒脉冲星开展近一个完整轨道周期的观测。因此，本提案申请为每个观测历元分配23小时的帕克斯UWL接收机观测时间，其中包含设备搭建与校准时间，以开展4颗蜘蛛类毫秒脉冲星的食掩机制、极化特性、脉冲轮廓演化及光谱研究。