Parkes observations for project P1375 semester 2025OCTS_04

Full description

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.

Notes

External Organisations
CSIRO - Australia Telescope National Facility; CSIRO - Space and Astronomy; CAS - Xinjiang Astronomical Observatory; CAS - Purple Mountain Observatory; Max Planck Institute for Plasma Physics - Garching, Germany

Associated Persons
Songbo Zhang (Creator)George Hobbs (Creator); Lawrence Toomey (Creator); Shi Dai (Creator); Shuangqiang Wang (Creator); Xuefeng Wu (Creator); Junjie Wei (Creator); Xuan Yang (Creator); Jieshuang Wang (Creator)