阿根廷射电天文研究所首次快速射电暴搜寻项目
First fast radio burst search campaign at the Argentine Institute of Radio Astronomy
AI总结：
阿根廷射电天文研究所开展首次FRB搜寻项目，利用30米天线等设备观测南天超星系团，通过PRESTO和FETCH识别出疑似FRB，或为南美首个FRB，结果支持项目扩展。
AI中文摘要：
快速射电暴（FRBs）是河外起源的毫秒级强烈射电瞬变，其物理本质仍在积极研究中，同时也可作为探测星系际介质的探针。我们报告了阿根廷射电天文研究所（IAR）于2024年12月至2026年3月开展的首次FRB搜寻项目，目标为南天的近域星系超星系团。我们使用IAR的两台30米天线之一，对蛇夫座、沙普利以及 Sculptor/Phoenix 超星系团区域的天区进行观测，采用基于ROACH的后端，带宽400 MHz，中心频率1400 MHz，时间分辨率41–82 μs，总净观测时间212小时。我们使用PRESTO软件在色散量（DM）范围100 ≤ DM ≤ 500内搜寻色散单脉冲，并用FETCH机器学习分类器对候选体进行分类。该流程在包含已知FRB的档案Parkes数据以及注入IAR观测的合成暴上得到验证。2025年10月18日，我们在对凤凰超星系团内星系团A2870的指向观测中识别出一个FRB候选体FRB 20251018，其色散量为243，信噪比8.2，FETCH概率p=0.99。据我们所知，这将是南美洲探测到的首个FRB。我们还呈现了一组边缘性更高的候选体。这些结果证明了IAR天线探测FRB的能力，并支持该监测项目的延续与扩展，包括同步双天线观测，以及与引力波事件和电磁瞬变的交叉匹配。
英文摘要：
Fast radio bursts (FRBs) are intense millisecond-duration radio transients of extragalactic origin whose physical nature remains under active investigation, and which also serve as probes of the intergalactic medium. We report on the first FRB search campaign carried out at the Argentine Institute of Radio Astronomy (IAR) between December 2024 and March 2026, targeting nearby galaxy superclusters in the southern sky. We observed fields in the Ophiuchus, Shapley, and Sculptor/Phoenix supercluster regions with one of the two 30~m antennas of the IAR, using a ROACH-based backend with 400~MHz of bandwidth centred at 1400~MHz and a time resolution of 41--82~$μ$s, for a total net observing time of 212~h. The data were searched for dispersed single pulses with \texttt{PRESTO} in the dispersion measure range $100 \leq \mathrm{DM} \leq 500$, and candidates were classified with the FETCH machine learning classifier. The pipeline was validated on archival Parkes data containing known FRBs and on synthetic bursts injected into IAR observations. One FRB candidate, FRB~20251018, was identified on 18 October 2025 in an observation pointed towards the galaxy cluster A2870, in the Phoenix supercluster, with a dispersion measure of $243$, a signal-to-noise ratio of 8.2, and a FETCH probability of $p=0.99$. To the best of our knowledge, this would be the first FRB detected from South America. A set of more marginal candidates is also presented. These results demonstrate the capability of the IAR antennas to detect FRBs and support the continuation and extension of the monitoring campaign, including coincident dual-antenna observations and cross-matches with gravitational-wave events and electromagnetic transients.
