快速射电暴中宿主色散量-恒星质量关系的局域起源
The Local Origin of a Host Dispersion Measure-Stellar Mass Relation in Fast Radio Bursts
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中文总结 AI 辅助
本研究利用37个FRB样本，发现其宿主的DM_host与恒星质量呈显著反相关，排除ISM和CGM的影响后，认为该关系源于局域环境，为FRB起源研究提供了新视角。
中文摘要 AI 辅助
快速射电暴（FRBs）的起源及其与宿主星系环境的关联仍是未解决的问题。本研究利用37个在红移z≲0.25处有可靠宿主关联的FRB样本，涵盖矮星系、椭圆星系和侧向星系，分析了宿主色散量（DM_host）及其与宿主恒星质量（M_⋆）的依赖关系。我们发现宿主色散量与宿主恒星质量之间存在统计显著的反相关（即DM_host-M_⋆关系，皮尔逊相关系数r≈-0.5，log₁₀p≈-2.8），该关系在样本的整个恒星质量范围log₁₀(M_⋆/M_⊙)≈8~11.4内均存在。我们还发现，静止帧法拉第旋转量（|RM|_host）在位于矮星系中的FRB中最大，但在整个质量范围内无相关证据。研究表明，DM_host-M_⋆趋势并非源于星系平均星际介质（ISM）或星系周介质（CGM），而是由局域（≲100秒差距）环境导致；恒星形成的空间分布及与金属丰度相关的FRB前身星通道，可能使低质量星系形成更致密的电离环境，而大质量星系的近邻气体则更少。
英文摘要
The origin of fast radio bursts (FRBs) and the relationship to their host galaxy environments remain open questions. Using a sample of 37 FRBs with secure host associations at $z \lesssim 0.25$, and including dwarf, elliptical, and edge-on hosts, we examine the host dispersion measure ($\mathrm{DM_{host}}$) and its dependence on host stellar mass ($M_\star$). We find a statistically significant anti-correlation between the host dispersion measure and host stellar mass (the $\mathrm{DM_{host}}$-$M_\star$ relation; Pearson $r \approx -0.5$, $\log_{10} p \approx -2.8$) that extends across the full range of our sample, $\log_{10}(M_\star/M_\odot) \approx 8$-$11.4$. We find that the rest-frame Faraday rotation measure ($|\mathrm{RM}|_{\mathrm{host}}$) is largest in FRBs that reside in dwarf galaxies, but there is no evidence for a correlation across the full mass range. We show that the $\mathrm{DM_{host}}$-$M_\star$ trend does not arise from the galaxy-averaged interstellar medium (ISM) nor from the circumgalactic medium (CGM). Instead, we argue that the local ($\lesssim 100$ pc) environment is responsible. The spatial statistics of star formation and metallicity-dependent FRB progenitor channels plausibly lead to denser ionized environments in low-mass galaxies and less nearby gas in massive hosts.
