Parkes observations for project P1375 semester 2025OCTS_04

Open clusters have historically shown a striking absence of neutron stars due to their shallow gravitational potential wells that cannot retain these compact objects after supernova explosions with large natal kicks. However, our recent archival search of Parkes observations has discovered three promising Rotating Radio Transient (RRAT) candidates, RRAT J1749-25, RRAT J1702-44, and RRAT J1237-60, in the direction of old open clusters. The dispersion measure (DM) analysis provides compelling evidence for cluster membership, with RRAT J1749-25 showing DM consistent with Theia 1661's predicted values, and RRAT J1237-60 exhibiting DM comparable to Trumpler 20's expectations. These detections are based on limited single-pulse observations with signal-to-noise ratios of ~7-8, requiring confirmation through extended observations. We propose follow-up observations using the Parkes Ultra-Wideband Low receiver with doubled integration times (2 hours per source, repeated twice) to confirm the astrophysical nature of these candidates and characterise their emission properties. Confirmation of neutron stars in open clusters would have profound implications for stellar evolution models, neutron star retention mechanisms, and our understanding of binary evolution in different stellar environments.疏散星团（open clusters）长期以来均呈现出中子星显著缺失的特征，究其根源在于其引力势阱较浅，无法在伴随大新生反冲的超新星爆发后留存这类致密天体。然而，我们近期对帕克斯（Parkes）望远镜观测档案的检索工作，在老年疏散星团的方向上发现了三颗极具潜力的旋转射电暂现源（Rotating Radio Transient, RRAT）候选体：RRAT J1749-25、RRAT J1702-44与RRAT J1237-60。色散量（dispersion measure, DM）分析为这些候选体属于星团成员提供了有力证据：RRAT J1749-25的色散量与Theia 1661的理论预测值相符，而RRAT J1237-60的色散量则与特朗普勒20（Trumpler 20）的预期值相当。此次探测基于信噪比约为7至8的有限单脉冲观测数据，因此需要通过后续扩展观测完成验证。我们提议使用帕克斯望远镜的超宽带低频段接收机（Ultra-Wideband Low receiver）开展后续观测，将积分时间翻倍（每个源观测2小时，重复两次），以确认这些候选体的天体物理本质并表征其辐射特性。若能证实疏散星团中存在中子星，将对恒星演化模型、中子星留存机制，以及我们对不同恒星环境下双星演化的认知产生极为深远的影响。