Parkes observations for project P1041 semester 2023OCTS_04

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 Omega Centauri）中发现的毫秒脉冲星（millisecond pulsars, MSPs）的长期计时观测项目。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）接收系统开展月度观测，以对已发现的脉冲星进行计时研究并搜寻新的脉冲星。基于约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。我们还将估算脉冲星视向加速度的上限，并与基于星团解析模型的理论预测进行对比。PSR J1326-4728的线偏振辐射给出的旋转测度（rotation measure）为-18(8) rad/m²。对这些毫秒脉冲星的长期计时观测将为我们提供三种全新的研究途径：（1）探究星团核心的动力学特性，约束中等质量黑洞（intermediate-mass black holes）的存在性；（2）揭示星团核心的伽马射线辐射（Gamma-ray emission）起源，并对暗物质（dark matter）参数施加严格限制；（3）在秒差距尺度（parsec scales）上研究银河系电离介质（Galactic ionised medium）与磁场。