发表机构
The Hong Kong Institute for Astronomy and Astrophysics (HKIAA), The University of Hong Kong; Department of Physics, The University of Hong Kong（香港大学天文学及天体物理研究所; 香港大学物理系）
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目录2中的一千多个非重复事件，通过结合反向非参数推理和正向群体合成的自洽框架推断快速射电暴的内在特征，发现其红移分布峰值与宇宙恒星形成历史峰值不同，表明至少部分快速射电暴有延迟。
AI 中文摘要
快速射电暴（FRBs）是发光的河外射电瞬变源，其物理起源尚不确定。利用CHIME/FRB目录2中的一千多个非重复事件，我们用一个自洽框架推断FRB的内在特征，该框架结合了反向非参数推理和正向群体合成，同时考虑了概率色散测量 - 红移估计、基带与目录流量校正以及最新的模糊多维选择函数。我们首先应用反向非参数方法，加权Lynden - Bell $C^{-}$估计器，在不假设任何群体模型的情况下恢复内在红移和能量分布。独立地，我们在可观测的色散测量 - 流量空间中进行正向蒙特卡罗群体合成，将候选的内在红移和能量分布视为群体假设，并将生成的选定合成目录与观测结果进行比较。我们发现内在红移分布在$z\sim1$处达到峰值，明显低于宇宙恒星形成历史（SFH）在$z\sim1.7$处的峰值，这表明与纯SFH跟踪场景存在明显矛盾，表明至少一些FRB相对于SFH有延迟。内在能量分布与指数$\alpha\approx1.9$的幂律一致，并且在更高能量处变陡。我们没有发现红移 - 能量分布相关性的显著证据。
英文摘要
Fast radio bursts (FRBs) are luminous extragalactic radio transients whose physical origins remain uncertain. Using over one thousand non-repeating events from CHIME/FRB Catalog 2, we infer the intrinsic FRB demographics with a self-consistent framework that combines backward non-parametric inference and forward population synthesis while accounting for probabilistic dispersion measure--redshift estimates, baseband-to-catalog fluence corrections, and the latest fuzzy multidimensional selection function. We first apply a backward non-parametric method, the weighted Lynden--Bell $C^{-}$ estimator, to recover the intrinsic redshift and energy distributions without assuming any population model. Independently, we perform forward Monte Carlo population synthesis in observable dispersion measure--fluence space, treating candidate intrinsic redshift and energy distributions as population hypotheses and comparing the resulting selected synthetic catalogs with observations. We find that the intrinsic redshift distribution peaks at $z\sim1$, significantly lower than the cosmic star formation history (SFH) peak at $z\sim1.7$, indicating clear tension with a pure SFH-tracking scenario, suggesting that at least some FRBs are delayed with respect to SFH. The intrinsic energy distribution is consistent with a power law of index $α\approx1.9$ and steepens at higher energies. We find no significant evidence for a redshift-energy distribution correlation.
CommentsAccepted by ApJ
