Parkes observations for project P1041 semester 2023OCTS_01

We propose to continue our long-term timing campaign of millisecond pulsars (MSPs) discovered in the Globular Cluster Omega Centauri. So far, we have discovered seven MSPs and obtained coherent timing solutions for five of them. Monthly observations with the Parkes Ultra-Wideband Low (UWL) receiver system are requested to time known pulsars and search for new pulsars. With a timing baseline of ~3.5 yr we are able to measure the derivative of the spin frequency for the first five pulsars. Upper limits on the pulsar line-of-sight acceleration are estimated and compared with predictions based on analytical models of the cluster. The linearly polarised emission from PSR J1326-4728 yields a rotation measure of -18(8) rad/m^2. Long-term timing observations of these MSPs will provide us a new way to (1) study the dynamics of the core and constrain the existence of any intermediate-mass black holes; (2) reveal the origin of Gamma-ray emission from the core and put stringent constraints on dark matter parameters; (3) study Galactic ionised medium and magnetic fields on parsec scales.本研究拟延续针对半人马座ω球状星团（Globular Cluster）中发现的毫秒脉冲星（millisecond pulsars, MSPs）开展的长期计时观测计划。截至目前，我们已发现7颗毫秒脉冲星，并为其中5颗获得了相干计时解。我们申请使用帕克斯超宽频低（Ultra-Wideband Low, UWL）接收机系统开展月度观测，以对已知脉冲星进行计时并搜寻新的脉冲星。依托约3.5年的计时基线，我们可对前5颗脉冲星的自旋频率导数进行测量。我们估算了脉冲星视线方向加速度的上限，并将其与基于该球状星团解析模型得到的理论预测进行对比。脉冲星PSR J1326-4728的线偏振辐射给出的旋转量为-18(8) rad/m²。对这些毫秒脉冲星开展的长期计时观测将为我们提供三项全新的研究途径：其一，研究星团核心的动力学特性，并约束任何可能存在的中等质量黑洞（intermediate-mass black holes）；其二，揭示星团核心的伽马射线辐射起源，并对暗物质参数施加严格的约束；其三，研究秒差距尺度下的银河系电离介质与磁场。