Parkes observations for project P1334 semester 2024OCTS_03

The Galactic Centre is the most complex and dynamic region of our Galaxy. Radio images have revealed a plethora of filamentary structures that trace out magnetic fields running perpendicular to the Galactic plane. Exactly what powers the radio emission of these filaments had remained a mystery, until the serendipitous discovery of a pulsar embedded in one. With a spin-period of 8.4 ms, PSR J1744-2946 is the first ever millisecond pulsar to be discovered in the central region of our Galaxy. While an exciting discovery in its own right, the limited timing baseline leaves open several unanswered questions: How efficiently is the pulsar injecting energy into the radio filament? Could the pulsar be included in pulsar timing array experiments? And can it be used as a key component in the search for axion dark matter? In this proposal we will use the Ultra-Wideband Low receiver system on Murriyang to conduct regular, monthly observations of PSR J1744-2946. This will provide us with a measurement of the pulsar spin-down rate and a sense of its long-term stability, thereby providing answers to the questions posed above.

银河系中心（Galactic Centre）是银河系中结构最为复杂、动力学特性最为活跃的区域。射电图像已揭示出大量丝状结构，这些结构勾勒出垂直于银道面（Galactic plane）的磁场分布。此前，究竟是什么为这些丝状结构的射电辐射提供能量，长期以来一直是未解之谜，直至人们在其中一条丝状结构内偶然发现了一颗嵌入其中的脉冲星（pulsar）。这颗编号为PSR J1744-2946的脉冲星自转周期为8.4毫秒，是人类首次在银河系中心区域发现的毫秒脉冲星（millisecond pulsar）。尽管这一发现本身已颇具科学意义，但受限于有限的计时基线，仍遗留多个悬而未决的问题：该脉冲星向射电丝状结构注入能量的效率如何？该脉冲星能否被纳入脉冲星计时阵列（pulsar timing array）实验？以及它能否作为关键组分用于轴子暗物质（axion dark matter）的搜寻？在本研究提案中，我们将利用Murriyang望远镜上的超宽带低接收机系统（Ultra-Wideband Low receiver system），对PSR J1744-2946开展每月一次的常规观测。本次观测将帮助我们测定该脉冲星的自转减速率，并掌握其长期稳定性，从而为上述所有问题提供解答。