来自非定向低频巡天的一次快速射电暴
A fast radio burst from a non-targeted low-frequency survey
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中文总结 AI 辅助
本文报道了利用默奇森宽场阵列进行宽视场成像巡天，首次在300 MHz以下非定向探测到快速射电暴，其发生率与高频一致，挑战了散射或吸收解释，并支持低频观测研究FRB环境。
中文摘要 AI 辅助
快速射电暴（FRB）是来自河外星系的明亮、毫秒级瞬态射电信号，其源和辐射机制尚不明确。虽然在400 MHz以上的频率已发现了数千个快速射电暴，但在较低频率下的探测却极为罕见。造成其罕见性的因素包括数十秒量级的色散延迟放大效应以及信号散射，这些因素使得利用既有技术进行低频搜索在计算上难以实现。特别是，在300 MHz以下唯一确认的探测来自针对FRB 20180916B（一个已知在更高频率发射的源）的低频阵列（LOFAR）观测活动。在此，我们报告了在300 MHz以下首次非定向探测到快速射电暴，该探测是在默奇森宽场阵列（MWA）进行的宽视场、基于成像的巡天中实现的。由此推算的快速射电暴发生率与在更高频率观测到的发生率一致，表明非定向宽视场巡天能够揭示无偏的、数量众多的高频快速射电暴群体。这一结果对先前用严重散射或吸收来解释未探测到的模型提出了挑战，并增强了低频观测作为研究快速射电暴局部环境的有前景途径的论据。
英文摘要
Fast radio bursts (FRBs) are bright, millisecond-duration transient radio signals of extragalactic origin with unknown source and emission mechanisms. While several thousand FRBs have been discovered at frequencies above 400 MHz, detections at lower frequencies have been exceptionally rare. Contributing to their rarity are the magnified dispersive delay, in the tens of seconds, and signal scattering that make low-frequency searches with established techniques computationally prohibitive. In particular, the only confirmed detection below 300 MHz came from a Low-Frequency Array observing campaign targeted at FRB 20180916B, a source already known to emit at higher frequencies. Here we present the first non-targeted detection of an FRB below 300 MHz, achieved in a wide-field, imaging-based survey with the Murchison Widefield Array. The implied FRB rate is consistent with that observed at higher frequencies, demonstrating that non-targeted wide-field surveys can uncover an unbiased, large low-frequency FRB population. This result challenges models invoking severe scattering or absorption to explain previous non-detections, and strengthens the case of low-frequency observations as promising avenue to study the local environment of FRBs.
发表机构
- Pawsey Supercomputing Research Centre（Pawsey超级计算研究中心）
- International Centre for Radio Astronomy Research (ICRAR), Curtin University（伊拉穆鲁大学国际射电天文研究中心）
- Australian SKA Regional Centre (AusSRC), University of Western Australia（西澳大利亚大学澳大利亚SKA区域中心）
- SKA Observatory (SKAO)（平方公里阵列望远镜观测站）
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