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arXiv 2406.03809astro-ph.HEastro-ph.CO
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快速射电暴族群相对于恒星形成历史的时间延迟

Time delay of fast radio burst population with respect to the star formation history

Hai-Nan Lin, Xin-Yi Li, Rui Zou

AI总结:

本研究基于首个CHIME/FRB星表构建贝叶斯框架,考虑望远镜选择效应,对比四种红移模型后发现对数正态延迟模型拟合最优,明确排除FRB族群追踪恒星形成历史的假设,测得其相对恒星形成历史平均有30~50亿年时间延迟。

摘要:

尽管近十年来快速射电暴(FRBs)研究取得了显著进展,但其起源仍存在广泛争议。对FRB族群的研究可为这一有趣问题提供新的见解。本文基于首个CHIME/FRB星表,构建了一个贝叶斯框架来分析FRB族群,且恰当考虑了CHIME望远镜的选择效应。能量函数被建模为带有指数截断的幂律形式。研究考虑了四种红移分布模型,即恒星形成历史(SFH)模型,以及三种时间延迟模型(高斯延迟、对数正态延迟和幂律延迟)。利用贝叶斯推断方法对自由参数进行同时约束,并采用贝叶斯信息准则(BIC)进行模型比较。根据BIC结果,对数正态延迟模型对数据的拟合效果最佳。幂律延迟模型和高斯延迟模型虽不如对数正态延迟模型,但也能给出合理的拟合结果。然而,与三种时间延迟模型相比,SFH模型被强烈排除。能量函数得到了严格约束,且几乎与红移模型无关,其最佳拟合幂律指数$α\neq 1.8$,截断能量$\text{log}(E_c/{\rm erg})\neq 42$。FRB族群相对于SFH平均表现出30~50亿年的时间延迟。因此,FRB族群追踪SFH的假设被明确排除。

英文摘要:

In spite of significant progress in the research of fast radio bursts (FRBs) in recent decade, their origin is still under extensive debate. Investigation on the population of FRBs can provide new insight into this interesting problem. In this paper, based on the first CHIME/FRB catalog, we construct a Bayesian framework to analyze the FRB population, with the selection effect of the CHIME telescope being properly taken into account. The energy function is modeled as the power-law with an exponential cutoff. Four redshift distribution models are considered, i.e., the star formation history (SFH) model, and three time-delayed models (Gaussian delay, log-normal delay, and power-law delay). The free parameters are simultaneously constrained using Bayesian inference method, and the Bayesian information criterion (BIC) is used in model comparison. According to BIC, the log-normal delay model fits the data best. The power-law delay model and Gaussian delay model can also give reasonable fits, although they are not as good as the log-normal delay model. However, the SFH model is strongly disfavored compared with the three time-delayed models. The energy function is tightly constrained and is almost independent of the redshift models, with the best-fitting power-law index $α\approx 1.8$, and cut-off energy $\log(E_c/{\rm erg})\approx 42$. The FRB population shows on average $3\sim 5$ billion years time delay with respect to the SFH. Therefore, the hypothesis that the FRB population traces the SFH is conclusively ruled out.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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