Parkes observations for project P1380 semester 2025OCTS_03

The association of FRB 200428 with the Galactic magnetar SGR 1935+2154 confirms that magnetars can power fast radio bursts (FRBs). However, FRB 200428 is 4 to 8 orders of magnitude less energetic than the typical population of cosmological FRBs. This discrepancy is likely due to the moderate magnetic field strength and evolved age of SGR 1935+2154. In contrast, newborn extragalactic magnetars, such as those formed in gamma-ray burst (GRB) central engines, are expected to have much stronger magnetic fields, more rapid spin-down, and highly dynamic magnetospheres, all of which favor the production of brighter and more frequent FRBs.

We propose a targeted search for FRBs from the recently localized GRB 230307A, a long-duration GRB with evidence suggesting the formation of a young magnetar. Given the source's relatively close distance (291 Mpc) and possible youth (less than 3 years), it offers a compelling opportunity to test FRB generation mechanisms during the early evolution of a magnetar.

We request 30 hours of observing time with the Parkes 64-m Murriyang telescope using the ultra-wideband low-frequency (UWL) receiver. Our plan includes one 10-hour long-duration session to detect rare or clustered bursts, and ten 2-hour sessions spread over 2-3 months to sample temporal variability. Data will be processed with state-of-the-art pipelines for single-pulse searches and coherent dedispersion.

A detection would strongly support magnetar-origin FRB models and provide key constraints on the early-time activity of GRB-formed neutron stars.

FRB 200428与银河系磁星软γ重复暴（Soft Gamma Repeater, SGR）1935+2154的关联，证实了磁星可以为快速射电暴（Fast Radio Burst, FRB）提供能量来源。不过，FRB 200428的能量相较于典型宇宙学快速射电暴种群低4至8个数量级。这一差异可能源于SGR 1935+2154中等强度的磁场以及其演化较久的年龄。与之相反，新生河外磁星——例如形成于伽马射线暴（Gamma-Ray Burst, GRB）中心引擎的磁星——预计拥有强得多的磁场、更快的自转减速以及高度动态的磁层，所有这些特性都更有利于产生更明亮、更频繁的快速射电暴。

我们提议对近期定位的GRB 230307A开展靶向搜寻，该源为长持续时间伽马射线暴，有证据表明其形成了年轻磁星。鉴于该源相对较近的距离（291 Mpc）以及可能的极年轻状态（不足3年），它为检验磁星早期演化阶段的快速射电暴产生机制提供了极具说服力的观测机会。

我们申请使用帕克斯64米穆里扬望远镜（Parkes 64-m Murriyang telescope）的超宽频低频（Ultra-Wideband Low-Frequency, UWL）接收机开展共计30小时的观测。我们的观测计划包含一次时长10小时的长时段观测，用于探测稀有或成簇出现的暴信号，以及10次时长2小时的观测时段，分布在2至3个月内以采样时域变异性。数据将使用用于单脉冲搜寻和相干去色散的前沿处理流水线进行处理。

若探测到快速射电暴，将有力支持磁星起源的快速射电暴模型，并为伽马射线暴形成的中子星的早期活动提供关键约束。