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arXiv 2101.08005astro-ph.HE
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快速射电暴的 z-DM 分布

The z-DM distribution of fast radio bursts

C. W. James, J. X. Prochaska, J. -P. Macquart, F. North-Hickey, K. W. Bannister, A. Dunning

AI总结:

本文开发了考虑宇宙学气体分布和宿主星系贡献的复杂FRB观测模型,详细分析了观测偏差对DM-z关系的影响,发现高DM时该关系会反转,并利用ASKAP和Parkes数据估算了FRB种群参数及分布特征。

摘要:

我们开发了一个复杂的 FRB 观测模型,考虑了内在的宇宙学气体分布和宿主星系贡献,并给出了迄今为止关于由于暴发宽度、色散量(DM)和精确的望远镜波束形状导致观测偏差的最详细说明。我们的结果在准确性和精确度上比以前获得的结果有显著提高。使用 ASKAP 和 Parkes 的结果,我们在一篇配套论文中给出了最佳拟合的 FRB 种群参数。在这里,我们详细考虑了红移、色散量和信噪比的预期和拟合分布。我们估计未定位的 ASKAP FRB 源于 z<0.5,其中三分之一到一半位于 z<0.1 内。我们预测的源计数(“logN-logS”)分布证实了先前关于在 Parkes 探测阈值 1 Jy ms 附近存在陡化指数的迹象。我们没有发现 FRB 最小能量的证据,并在 90% 置信水平上排除了 Emin > 10^39.0 erg。重要的是,我们发现高于特定 DM 时,观测偏差导致 Macquart(DM-z)关系发生反转,这意味着在未定位的 Parkes 和 ASKAP 样本中探测到的最高 DM 事件不太可能是最遥远的。尽管其原因是一个充分了解的观测偏差,但仍需要更多定位的 FRB 来定量估计这种效应。因此,假设 1-1 DM-z 关系的研究可能会得出错误的结果。我们的误差分析表明,我们分析中的限制因素是对 FRB 光谱行为、搜索实验的灵敏度响应以及重复种群和光度函数处理的理解。

英文摘要:

We develop a sophisticated model of FRB observations, accounting for the intrinsic cosmological gas distribution and host galaxy contributions, and give the most detailed account yet of observational biases due to burst width, dispersion measure, and the exact telescope beamshape. Our results offer a significant increase in both accuracy and precision beyond those previously obtained. Using results from ASKAP and Parkes, we present our best-fit FRB population parameters in a companion paper. Here, we consider in detail the expected and fitted distributions in redshift, dispersion measure, and signal-to-noise. We estimate that the unlocalised ASKAP FRBs arise from $z<0.5$, with between a third and a half within $z<0.1$. Our predicted source-counts (''logN-logS'') distribution confirms previous indications of a steepening index near the Parkes detection threshold of $1$ Jy ms. We find no evidence for a minimum FRB energy, and rule out $E_{\rm min} > 10^{39.0}$ erg at 90% C.L. Importantly, we find that above a certain DM, observational biases cause the Macquart (DM-z) relation to become inverted, implying that the highest-DM events detected in the unlocalised Parkes and ASKAP samples are unlikely to be the most distant. More localized FRBs will be required to quantitatively estimate this effect, though its cause is a well-understood observational bias. Works assuming a 1-1 DM-z relation may therefore derive erroneous results. Our analysis of errors suggests that limiting factors in our analysis are understanding of FRB spectral behaviour, sensitivity response of search experiments, and the treatment of the repeating population and luminosity function.

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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