Parkes observations for project P1064 semester 2020APRS_02

The propagation of pulsar signal through the interstellar medium is affected by the fluctuations in the electron density in the line of sight from the pulsar to the observer. This is a frequency dependent phenomenon and will produce brightness variations (scintillation) and also broadening of the otherwise narrow pulse (scatter-broadening). The effect of these two are measurable at different frequencies due to their strong dependence on frequency, viz., broadening will be evident at lower radio frequencies and scintillation will be clearly resolved at higher frequencies. With this proposal, we aim to study the evolution of scatter-broadening and scintillation properties of 137 pulsars with the UWL receiver, and verify their relationship with each other. With this experiment, we aim at testing some of the fundamental theories of ionised interstellar medium. This large sample will also help in improving the understanding of the turbulence characteristics in the inner Galaxy. We request a total of 149 hours for this project.

脉冲星信号穿越星际介质（interstellar medium）的传播过程，会受到从脉冲星至观测者视线方向上电子密度涨落的影响。该现象具有频率依赖性，会引发亮度变化（星际闪烁scintillation），同时还会使原本窄脉冲产生展宽（散射展宽scatter-broadening）。由于这两种效应均与频率存在极强的依赖关系，因此它们在不同射电频率下的可观测性存在差异：散射展宽在低频射电波段更为显著，而星际闪烁则可在高频射电波段被清晰分辨。本项目拟依托UWL接收机，对137颗脉冲星的散射展宽与星际闪烁特性的演化规律展开研究，并验证二者之间的内在关联。本实验旨在检验电离星际介质（ionised interstellar medium）的若干基础理论，此次研究采用的大样本同样有助于加深我们对银河系内区湍流特性的认知。本项目申请总观测时长共计149小时。