发表机构
California Institute of Technology; Owens Valley Radio Observatory, California Institute of Technology; Observatories of the Carnegie Institution for Science（加州理工学院; 加州理工学院欧文斯谷射电天文台; 卡内基科学研究所天文台）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究利用DSA-110探测的43个FRB样本，测量宿主星系对DM和RM的贡献，发现其过密磁化环境主导河外散射，支持FRB源于核坍缩超新星形成的磁星并关联HII区。
AI 中文摘要
我们刻画了用深综合阵列（DSA-110）探测到的一批快速射电暴（FRB）的源环境。我们展示了对24个已局域化到具有光谱红移的宿主星系的FRB样本的新分析。其中四个暴已确信与红移接近或超过1的星系相关联，且其中几个是首次在此发表。将这些新暴与先前分析过的DSA-110源相结合，我们使用一个包含43个已知红移的DSA-110 FRB的样本来测量宿主星系对色散量（DM）和法拉第旋转量（RM）的贡献。我们发现宿主星系对DM和RM的贡献特征性地大且显著相关，表明大多数FRB位于其宿主星系星际介质（ISM）中的过密、磁化区域。此外，我们识别出一个具有可探测散射的FRB子集，并表明它们的散射时标和推断的宿主DM值大致与为银河系脉冲星建立的经验关系一致。结合对某些暴的双屏建模，我们的结果表明宿主星系ISM内的密度涨落是河外散射的主要来源。将FRB宿主星系性质与脉冲星以及年轻和年老前身星种群的模拟进行比较，支持这样一种情景：FRB优先形成并终生与其HII区保持关联，这有利于由核坍缩超新星形成的磁星作为FRB的源。
英文摘要
We characterize the source environments of a sample of fast radio bursts (FRBs) detected with the Deep Synoptic Array (DSA-110). We present new analyses of a sample of 24 FRBs which have been localized to host galaxies with spectroscopic redshifts. Four of these bursts have been confidently associated with galaxies near or beyond redshift 1, and several are published here for the first time. Combining these new bursts with previously analyzed DSA-110 sources, we use a sample of 43 DSA-110 FRBs with known redshifts to measure host-galaxy contributions to dispersion measure (DM) and Faraday rotation measure (RM). We find characteristically large and significantly correlated host-galaxy contributions to DM and RM, suggesting that most FRBs reside in overdense, magnetized regions within their host ISM. Additionally, we identify a subset of FRBs with detectable scattering, and show that their scattering timescales and inferred host DM values are broadly consistent with an empirical relation established for Galactic pulsars. Combined with two-screen modeling of some bursts, our results indicate that density fluctuations within the host-galaxy ISM are the dominant source of extragalactic scattering. Comparisons of FRB host-galaxy properties with pulsars and simulations of young and old progenitor populations support a scenario in which FRBs preferentially form and remain associated with HII regions throughout their emission lifetime, favoring magnetars formed in core-collapse supernovae as the sources of FRBs.
Comments26 pages, 18 figures, 3 tables. Submitted to ApJ
