发表机构
Northwestern University; Princeton University; Center for Astrophysics | Harvard & Smithsonian（西北大学; 普林斯顿大学; 哈佛-史密森天体物理中心）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
利用CHIME/FRB Outrigger定位的FRB样本，发现重复暴与非重复暴的宿主星系金属丰度分布显著不同，重复暴偏好贫金属矮星系，且与持续射电源相关，暗示金属丰度依赖的前身星演化路径。
AI 中文摘要
利用CHIME/FRB Outrigger在2025年2月至10月期间定位的快速射电暴（FRBs），我们对其矮星系宿主进行了系统性搜索。我们为一个重复暴和七个表观非重复暴识别并刻画了八个宿主星系，其中五个宿主星系被新分类为矮星系，其恒星质量约为log(M_*/M_☉) ≈ 8.1-9.1。我们测量了它们的气相金属丰度，并结合文献中的宿主星系数据，发现重复暴和非重复暴具有统计上不同的金属丰度分布。非重复暴在整个观测质量范围内栖居于相对富金属的环境（12 + log(O/H) ≳ 8.35），而重复暴则显著偏好于12 + log(O/H) ≲ 8.35的矮星系。几乎所有与持续射电源（PRSs）相关的重复暴都位于12 + log(O/H) ≲ 8.15的矮星系中，这表明贫金属矮星系环境中的重复暴与PRS形成之间存在关联。我们还分别计算了54、37和24个FRBs的宿主色散量（DM_host）、法拉第旋转量（RM_host）和散射时标（τ_host,1 GHz），包括我们的样本和文献中的FRBs。我们发现宿主金属丰度与DM_host、RM_host或τ_host,1 GHz之间没有显著（>3σ）的相关性。表观非重复暴和重复暴的宿主金属丰度差异可能反映了金属丰度依赖的大质量恒星演化，重复暴和PRSs需要比主要非重复暴群体更极端的磁星诞生自旋。
英文摘要
Using the fast radio bursts (FRBs) localized with the CHIME/FRB Outriggers between February and October 2025, we conduct a systematic search for dwarf host galaxies. We identify and characterize eight host galaxies for one repeating and seven apparently non-repeating FRBs, newly classifying five hosts as dwarfs with stellar masses of $\log(M_\ast/M_\odot) \approx 8.1-9.1$. We measure their gas-phase metallicities and, when combined with hosts from the literature, finding that repeating and non-repeating FRBs have statistically distinct metallicity distributions. Non-repeating FRBs inhabit relatively metal-rich environments ($12 + \rm log( O/H) \gtrsim 8.35$) across the full observed mass range, while repeating FRBs have significant preference for dwarf galaxies with $12 + \rm log( O/H) \lesssim 8.35$. Almost all repeaters associated with persistent radio sources (PRSs) are in dwarfs with $12 + \rm log( O/H) \lesssim 8.15$, suggesting a connection between repeaters in metal-poor dwarf environments and PRS formation. We also calculate the host dispersion measure ($\mathrm{DM}_{\rm host}$), Faraday rotation measure ($\mathrm{RM}_{\rm host}$), and scattering timescale ($τ_{\rm host,1~GHz}$) for 54, 37, and 24 FRBs, respectively, including both our sample and FRBs in the literature. We find no significant ($>3σ$) correlation between host metallicity and $\mathrm{DM}_{\rm host}$, $\mathrm{RM}_{\rm host}$, or $τ_{\rm host,1~GHz}$. The distinct host metallicities of apparently non-repeating and repeating FRBs may reflect metallicity-dependent massive-star evolution, with repeating FRBs and PRSs requiring more extreme magnetar birth spins than the predominantly non-repeating FRB population.
CommentsSubmitted to ApJ. 32 pages, 10 figures, and 6 tables
