Parkes observations for project P1172 semester 2023APRS_08

PSR J1713+0747 is a very important millisecond pulsar for global pulsar timing array campaigns, due to its long-term observation history, very stable and narrow profile and strong S/N. In April 2021, the pulsar experienced a significant event related to a change in its magnetosphere, presented as an observable change in the pulsar profile. Since then, the pulsar has been slowly recovering and we wish to observe this recovery with high-cadence observations to allow us to create a detailed time-resolved series of variations in the MSPs profile, polarisation, and other properties. Under this proposal, we wish to probe the profile recovery on weekly timescales (once per week per month), revealing additional short timescale behaviours, indicative of changes in the magnetosphere which are not available to other telescopes in the world, thanks to the Parkes UWL. This will also allow us to determine if the magnetosphere has returned to its original configuration or is settling into a new one. Understanding the recovery of this event is key for demonstrating that such pulsars are still viable clocks for use in gravitational wave studies, and in turn, provide us with new data on how the normally stable magnetosphere of this millisecond pulsar responds to an impulsive change in state.

PSR J1713+0747是全球脉冲星计时阵列（pulsar timing array, PTA）观测计划中至关重要的一颗毫秒脉冲星（millisecond pulsar, MSP），凭借其长期观测历史、轮廓极稳定且狭窄、信噪比（signal-to-noise ratio, S/N）高等优势，成为该计划的核心观测目标之一。
2021年4月，该脉冲星发生了一起与其磁层（magnetosphere）变化相关的显著事件，表现为脉冲星轮廓出现可观测到的改变。自此之后，该毫秒脉冲星进入缓慢恢复阶段，我们计划通过高频次观测对这一恢复过程进行监测，以获取该MSP轮廓、偏振（polarisation）及其他特性随时间变化的高分辨时序序列。
基于本观测提案，我们将以周为时间尺度开展观测（每月内每周观测一次），以期捕捉到更多此前未被发现的短时标行为特征——这类特征可反映磁层的内部变化，而依托帕克斯（Parkes）UWL设备，全球其他望远镜均无法获取此类珍贵观测数据。本计划还将帮助我们判断该脉冲星的磁层是否已恢复至初始构型，或是正逐渐稳定于全新的磁层结构。
厘清此次事件后的恢复过程，对于证明这类毫秒脉冲星仍可作为引力波研究中的可靠计时钟至关重要；同时也将为我们提供全新的观测数据，用以揭示这颗通常处于稳定状态的毫秒脉冲星的磁层，是如何响应状态的突发性改变的。