Parkes observations for project P1356 semester 2025APRS_07

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.
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（Magnetars）是一类具有极高磁场的中子星。在已知的30颗磁星中，迄今仅探测到6颗存在射电辐射。剩余24颗磁星通常仅在X射线爆发后才会被搜索射电辐射，这为判断磁星是否为射电明亮型引入了强烈的选择偏差。从已知的6颗射电明亮型磁星来看，其射电辐射随时间快速变化；对于磁星XTE J1810-197，观测显示其射电流量显著增加时，X射线流量并未增强。因此，目前尚不清楚射电宁静型磁星是否真的射电宁静，且射电与X射线之间的关系似乎相当复杂。
本提案计划利用Parkes UWL接收器对4颗射电宁静型磁星开展定期监测，观测频率为每两周一次。其中3个源将同步进行X射线观测，由此可获得独特的数据集，用于探究射电与X射线独立爆发之间的关系。若探测到射电辐射（如单脉冲或折叠轮廓），将是一项重大发现，有助于约束磁星的辐射机制，同时深化对快速射电暴辐射机制的理解。即便未探测到射电辐射，所得的上限值也可作为观测磁星未来爆发前的基准，同时助力对比约束磁星与脉冲星的形成过程。