Parkes observations for project P1172 semester 2022OCTS_01

PSR J1713+0747 is an extremely stable millisecond pulsar used in global pulsar timing array campaigns as a high priority pulsar because of its strong S/N, narrow profile and long-term observation history. In April 2021, the pulsar experienced a significant event related to a change in its magnetosphere, presented as an observable change in the pulsar’s profile. Since then, the pulsar has been slowly recovering and we wish to observe it with high cadence 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 daily timescales (3 times per week with 2 day intervals in between), 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是一颗极端稳定的毫秒脉冲星（millisecond pulsar, MSP），因其信噪比（Signal-to-Noise Ratio, S/N）高、轮廓狭窄且具备长期观测历史，被全球脉冲星计时阵列（pulsar timing array, PTA）项目列为优先观测目标。
2021年4月，该脉冲星发生了与磁层（magnetosphere）变化相关的显著事件，表现为脉冲轮廓出现可观测的改变。此后该星正缓慢恢复，我们计划以高观测频次开展监测，以获取该毫秒脉冲星的轮廓、偏振（polarisation）及其他属性的时间分辨演化序列。
根据本观测提案，我们拟以日尺度开展轮廓恢复过程的观测（每周3次，两次观测间隔2天），以此揭示此前未被捕捉到的短时标行为——这类变化可反映磁层的动态调整，而依托帕克斯超宽波段（Parkes UWL）系统，这类观测是全球其他望远镜无法实现的。该观测计划还将帮助我们判断该磁层是否已恢复至初始构型，或是正逐渐稳定于新的平衡状态。
阐明此次事件后的恢复过程，对于验证这类脉冲星仍可作为引力波研究中的可靠时钟至关重要；同时也能为我们提供全新的观测数据，以揭示这颗通常处于稳定状态的毫秒脉冲星的磁层，是如何响应突发性状态改变的。