Parkes observations for project P1356 semester 2025APRS_17

Magnetars are neutron stars with exceptionally high magnetic fields. From the 30 known magnetars, only six have had radio emission detected so far. The remaining 24 magnetars are generally only searched for radio emission after an X-ray outburst. This added a strong selection bias to whether magnetars are radio loud or not. From the known six radio loud magnetars, we know that the radio emission changes quickly with time and for the magnetar XTE J1810-197, it has been observed that the radio flux increases strongly without an enhancement in X-ray flux. Thus, it remains unclear whether the radio quiet magnetars are in fact radio quiet and the radio X-ray relation appears to be rather complex.\n In this proposal, we propose a regular monitoring campaign of 4 radio quiet magnetars with bi-weekly observations using the Parkes UWL receiver. For 3 of the sources, we will have accompanying X-ray observations and thus, this will give an unique data set to probe the relation between radio and X-ray independent outbursts. Any detection of radio emission, i.e. single pulses or folded profiles, would be a major discovery and help to constrain the emission mechanisms of magnetars. This will also help to improve the understanding of the emission mechanism of fast radio bursts. However, also a non-detection of radio emission will provide upper limits that serve as a baseline before any future outburst of the observed magnetars as well as allow to constrain the formation process of magnetars in contrast to pulsars.

磁星（Magnetar）是拥有极强磁场的中子星。目前已发现的30颗磁星中，仅6颗被探测到射电辐射。剩余24颗磁星通常仅在发生X射线耀发后才会被开展射电辐射搜寻，这为判断磁星是否属于射电活跃样本引入了显著的选择偏差。在已知的6颗射电活跃磁星中，我们观测到其射电辐射会随时间快速变化；其中针对磁星XTE J1810-197的观测还发现，其射电流量出现显著提升时，X射线流量并未伴随增强。因此目前仍无法明确射电宁静磁星是否真的不产生射电辐射，且射电与X射线的关联机制看起来相当复杂。
在本研究提案中，我们计划利用帕克斯UWL接收机（Parkes UWL receiver），通过每两周一次的观测对4颗射电宁静磁星开展常态化巡测。其中3颗源将同步开展X射线观测，这将为我们提供独一无二的数据集，用以探究射电与X射线辐射在非耀发状态下的关联关系。若能探测到射电辐射（即单脉冲或折叠轮廓信号），将是一项重大发现，有助于约束磁星的辐射机制，同时也能加深我们对快速射电暴辐射机制的理解。即便未能探测到射电辐射，所得出的射电流量上限也将作为基准，为后续观测到的磁星发生耀发时提供对比依据，同时还能帮助我们约束相较于脉冲星而言的磁星形成过程。