Parkes observations for project P1356 semester 2025APRS_06

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）是一类拥有极强磁场的中子星。截至目前，在已发现的30颗磁星中，仅有6颗被探测到射电辐射。剩余的24颗磁星通常仅在其发生X射线暴后，才会被启动射电辐射搜寻工作，这为判断磁星是否属于射电明亮源引入了显著的选择偏差。在已知的6颗射电明亮磁星中，其射电辐射会随时间快速变化；针对磁星XTE J1810-197的观测结果还表明，其射电流量会出现显著增长，但X射线流量并未同步增强。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射线辐射的关联机制似乎相当复杂。
在本研究提案中，我们计划利用帕克斯（Parkes）UWL接收机，以每两周一次的观测频率，对4颗射电宁静磁星开展常规监测工作。其中3颗源将同步开展X射线观测，由此将获得一套独特的数据集，用于探究射电与X射线辐射在不依赖于暴发现象前提下的关联机制。若能探测到射电辐射（无论是单脉冲还是折叠脉冲轮廓），都将是一项重大发现，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（fast radio burst）辐射机制的理解。反之，若未探测到射电辐射，也将为后续观测的磁星发生暴发现象前提供射电流量上限作为参照基准，并有助于对比脉冲星，约束磁星的形成过程。