近日，美国卡耐基梅隆大学的Mohit Bhardwaj及其研究团队取得一项新进展。经过不懈努力，他们证实选择性偏差会模糊快速射电暴源的发现。相关研究成果已于2024年10月23日在国际权威学术期刊《自然》上发表。

本研究利用非定向巡天发现的FRB宿主星系样本，提供了实证证据，表明在检测大倾角（即边缘朝向）星系中的FRB时存在显著的选择偏差。这种与倾角相关的偏差可能导致文献中报道的FRB率被大幅低估（约低估一半），并且不利于先前推测的球状星团作为FRB源的主要起源。这些结论对FRB前身星模型和针对性的FRB后续观测策略具有重要意义。研究人员进一步研究了这一偏差对不同宿主环境中FRB相对率的影响。分析表明，FRB宿主星系中的散射可能是导致观测偏差的原因。然而，为了准确量化散射对与倾角相关的选择偏差的贡献，需要更多的已定位FRB样本。

据悉，快速射电暴（FRB）是一类新发现的河外星系射电瞬变现象，以高能量和短持续时间（从微秒到毫秒）为特征。这些FRB的物理起源尚不清楚，仍是当前研究的热点，其中磁星成为主要候选体。以往研究采用了多种方法来探讨FRB的起源问题，包括对FRB宿主星系及其局部环境的人口统计学分析、FRB率随红移变化的评估，以及寻找提出的多信使FRB对应体。然而，这些研究容易受到未考虑的射电和光学选择效应所带来的显著偏差影响。

附：英文原文

Title: Selection bias obfuscates the discovery of fast radio burst sources

Author: Bhardwaj, Mohit, Lee, Jimin, Ji, Kevin

Issue&Volume: 2024-10-23

Abstract: Fast radio bursts (FRBs) are a newly discovered class of extragalactic radio transients characterized by their high energy and short duration (from microseconds to milliseconds). The physical origin of these FRBs remains unknown and is a subject of ongoing research, with magnetars emerging as leading candidates. Previous studies have used various methodologies to address the problem of FRB origin, including demographic analyses of FRB host galaxies and their local environments, assessments of FRB rate evolution with redshift and searches for proposed multi-messenger FRB counterparts. However, these studies are susceptible to substantial biases stemming from unaccounted radio and optical selection effects. Here we present empirical evidence for a substantial selection bias against detecting FRBs in galaxies with large inclination angles (edge-on) using a sample of hosts identified for FRBs discovered by untargeted surveys. This inclination-related bias probably leads to a significant underestimation (by about a factor of two) of the FRB rates reported in the literature and disfavours globular clusters as the dominant origin of FRB sources, as previously speculated. These conclusions have important implications for FRB progenitor models and targeted FRB follow-up strategies. We further investigate the impact of this bias on the relative rate of FRBs in different host environments. Our analysis suggests that scattering in FRB hosts is probably responsible for the observed bias. However, a larger sample of localized FRBs is required to robustly quantify the contribution of scattering to the inclination-related selection bias.

DOI: 10.1038/s41586-024-08065-w

Source: https://www.nature.com/articles/s41586-024-08065-w