Parkes observations for project P456 semester 2023APRS_08

The Parkes Pulsar Timing Array (PPTA) project has three primary goals: (a) detection of gravitational waves from astronomical sources, (b) establishment of a pulsar timescale, and (c) improvement of our understanding of Solar-system dynamics. We are now in an exciting regime where a signal detected in our (and other data sets) has the form expected for a gravitational wave background. We are therefore now attempting to confirm, or deny, this exciting result. With this proposal we aim to maintain our pre-eminent position in the field.\r\n\r\nUnlike most observing proposals, this is a continuing proposal for which the observations will continue to improve bounds on ultra-low-frequency gravitational waves until they are finally detected. Continued Parkes observations will remain valuable at least until the first stage of the SKA is able to improve on our sensitivity and observing cadence. Even after the gravitational wave background is detected we will want to continue observations in support of the nascent field of gravitational wave astronomy!

Parkes脉冲星计时阵列（Parkes Pulsar Timing Array, PPTA）项目拥有三大核心目标：（a）探测来自天文天体的引力波，（b）建立脉冲星时标系统，（c）深化我们对太阳系动力学的认知。当前我们正处于一个令人振奋的研究阶段——我们在本次数据集（及其他数据集）中探测到的信号，其形态完全符合引力波背景的理论预期特征。因此我们正尝试确认或推翻这一突破性发现。本申请旨在维持我们在该领域的领先地位。

与大多数观测申请不同，本申请属于持续性观测项目，相关观测将持续优化超低频引力波的探测上限，直至最终实现该信号的直接探测。帕克斯望远镜的持续观测至少将保持其科学价值，直到平方公里阵列（Square Kilometre Array, SKA）的第一阶段项目能够在灵敏度与观测节奏上实现超越。即便在引力波背景被探测到之后，我们仍将持续开展观测工作，以支撑这一新兴的引力波天文学领域发展。