Parkes observations for project P456 semester 2023APRS_09

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!

帕克斯脉冲星计时阵列（Parkes Pulsar Timing Array, PPTA）项目拥有三大核心目标：（a）探测来自天体源的引力波；（b）建立脉冲星时标；（c）深化我们对太阳系动力学的认知。目前我们正处于一个令人振奋的研究阶段：我们（及其他数据集）中探测到的信号，其形态恰好符合引力波背景的预期特征。因此，我们当前正尝试验证或推翻这一振奋人心的探测结果。通过本申请，我们旨在维持自身在该领域的领先地位。

与多数观测申请不同，本项目属于持续性观测计划：观测工作将持续优化超低频引力波的探测上限，直至最终成功探测到该信号。帕克斯望远镜的持续观测至少将保持其科学价值，直至平方公里阵列（Square Kilometre Array, SKA）的第一阶段项目能够提升我们的探测灵敏度与观测频次。即便引力波背景被成功探测，我们仍将持续开展观测，以支撑这一新兴的引力波天文学领域的发展！