Parkes observations for project P1356 semester 2025APRS_05

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）是一类具备极强磁场的中子星。迄今已发现的30颗磁星中，仅有6颗被探测到射电辐射。剩余24颗磁星通常仅在发生X射线暴后才会被开展射电辐射搜寻，这为判定磁星是否属于射电亮源引入了显著的选择偏差。基于已发现的6颗射电亮磁星的观测数据，我们可知其射电辐射会随时间快速演化；其中针对磁星XTE J1810-197的观测显示，其射电流量大幅升高时，X射线流量并未出现相应增强。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，我们计划使用帕克斯UWL接收机（Parkes UWL receiver），对4颗射电宁静磁星开展每两周一次的常规监测计划。其中3颗源将配套开展X射线观测，由此可获得一套独特的数据集，用于探究射电与X射线辐射在脱离暴发性活动干扰时的关联关系。若探测到射电辐射（包括单脉冲信号或折叠后的辐射轮廓），都将是一项重大发现，有助于限定磁星的辐射机制，同时也能加深我们对快速射电暴（Fast Radio Bursts）辐射机制的理解。此外，即便未探测到射电辐射，也可获得射电流量上限数据，既可为后续观测的磁星暴发性活动提供基准基线，也能帮助限定磁星相较于脉冲星的形成过程。