Parkes observations for project P1172 semester 2022OCTS_13

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是一颗稳定性极强的毫秒脉冲星（millisecond pulsar, MSP），因其高信噪比（signal-to-noise ratio, S/N）、轮廓狭窄且拥有长期观测历史，被全球脉冲星计时阵列（pulsar timing array, PTA）观测项目列为优先观测目标。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到的显著变化。此后，该脉冲星始终处于缓慢恢复阶段，我们计划通过高频次观测获取其详细的时间分辨演化序列，涵盖该毫秒脉冲星的轮廓、偏振特性及其他物理属性的变化过程。基于本观测提案，我们拟以日尺度开展轮廓恢复过程的监测（每周3次，观测间隔为2天），以期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内部变化，而得益于Parkes UWL，这类信号是全球其他望远镜无法捕获的。本次观测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状态。阐明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时钟至关重要；同时也能为我们揭示这类通常保持稳定的毫秒脉冲星磁层，在遭遇突发性状态改变时的响应机制提供全新的观测数据。