Parkes observations for project P1363 semester 2025APRS_06

We propose to monitor the bursts from the hyperactive repeating fast radio burst FRB 20240619D over six months using the Murriyang UWL receiver. The primary aim is to study the evolution of burst activity and polarization properties with frequency and time, and to discover any potential periodicity in the burst activity. These insights will enhance our understanding of the progenitor, emission physics, and the immediate magneto-ionic environment of FRB 20240619D, thereby informing the general FRB population. A total of 15 hours of observing between August and November 2024 resulted in over 1300 bursts detected using the UWL receiver. Some bursts exhibit complex spectro-temporal emission patterns. The burst rate, based on Murriyang and MeerKAT observations, indicates that the source was active until September 2nd, after which it became inactive. Given that two other repeating FRBs have exhibited periodic activity cycles, it is reasonable to expect that FRB 20240619D could become active again, making continued monitoring crucial. The UWL receiver's broad frequency coverage and sensitivity are essential for detecting many bursts and enabling simultaneous observations at different frequencies. This is important for understanding the burst activity evolution with time and frequency, spectral properties, and underlying emission mechanisms. The combination of sensitivity and wide bandwidth makes Murriyang the ideal telescope for monitoring this FRB. Results from these observations will be pivotal in understanding FRB 20240619D's place within the broader repeater population and its potential connection to broader FRB progenitor models.

我们计划利用Murriyang UWL接收器，对超活跃重复快速射电暴（Fast Radio Burst，FRB）20240619D的爆发进行为期六个月的监测。主要目标是研究爆发活动及偏振特性（polarization properties）随频率和时间的演化规律，并探索爆发活动中可能存在的周期性。这些见解将深化我们对FRB 20240619D的前身天体（progenitor）、辐射物理机制及其紧邻磁离子环境（magneto-ionic environment）的理解，进而为研究FRB整体群体提供参考。2024年8月至11月期间，通过UWL接收器进行的总计15小时观测，成功探测到超过1300次爆发。部分爆发呈现出复杂的频谱-时间辐射模式（spectro-temporal emission patterns）。基于Murriyang和MeerKAT的观测结果，爆发率表明该源的活跃状态持续至9月2日，之后转为不活跃。鉴于另外两个重复FRB已表现出周期性活动循环，因此有理由推测FRB 20240619D可能会再次活跃，这使得持续监测至关重要。UWL接收器的宽频率覆盖范围和高灵敏度对于探测大量爆发事件及实现不同频率下的同步观测至关重要。这对于理解爆发活动随时间和频率的演化、频谱特性及潜在辐射机制（emission mechanisms）具有重要意义。灵敏度与宽带宽的结合使Murriyang成为监测该FRB的理想望远镜。这些观测结果将对明确FRB 20240619D在更广泛重复FRB群体中的定位及其与更普遍FRB前身天体模型的潜在关联起到关键作用。