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），因其高信噪比（signal-to-noise ratio, S/N）、脉冲轮廓窄且具备长期观测历史，被列为全球脉冲星计时阵列（pulsar timing array, PTA）巡天项目的高优先级观测目标。2021年4月，该脉冲星发生了一起与磁层变化相关的显著事件，表现为脉冲轮廓出现可观测的改变。此后该脉冲星持续处于缓慢恢复状态，研究团队计划以高观测频次开展观测，以获取该毫秒脉冲星的轮廓、偏振及其他属性随时间演化的高分辨率时序分辨序列。基于本观测提案，团队希望在日尺度观测周期下（每周3次，两次观测间隔2天）对脉冲轮廓的恢复过程进行探测，以揭示此前未被捕捉到的短时标行为——这类行为可反映磁层的变化，而得益于帕克斯超宽波段系统（Parkes UWL），这类信号是全球其他望远镜无法观测到的。本次观测还将帮助研究团队确定该脉冲星的磁层是否已恢复至初始状态，或是逐渐稳定至新的构型中。阐明此次事件的恢复过程，对于证实这类脉冲星仍可作为引力波研究中的可靠时钟至关重要；同时也能为我们揭示这颗通常处于稳定状态的毫秒脉冲星的磁层如何响应突发状态改变提供全新的观测数据。