Fast Radio Bursts (FRBs) represent a novel tool for probing the properties of the universe at cosmological distances. The dispersion measures of FRBs, combined with the redshifts of their host galaxies, has very recently yielded a direct measurement of the baryon content of the universe, and has the potential to directly constrain the location of the “missing baryons”. The first results are consistent with the expectations of ΛCDM for the cosmic density of baryons, and have provided the first constraints on the properties of the very diffuse intergalactic medium (IGM) and circumgalactic medium (CGM) around galaxies. FRBs are the only known extragalactic sources that are compact enough to exhibit diffractive scintillation in addition to showing exponential tails which are typical of scattering in turbulent media. This will allow us to probe the turbulent properties of the circumburst medium, the host galaxy ISM/halo, and intervening halos along the path, as well as the IGM. Measurement of the Hubble constant and the dark energy parameter w can be made with FRBs, but require very large samples of localised FRBs (>${10}^3$) to be effective on their own—they are best combined with other independent surveys to improve the constraints. Ionisation events, such as for He ii, leave a signature in the dispersion measure—redshift relation, and if FRBs exist prior to these times, they can be used to probe the reionisation era, although more than ${10}^3$ localised FRBs are required.

中文翻译：

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用快速无线电爆发探测宇宙

快速无线电爆发（FRB）代表了一种新颖的工具，可用于探测宇宙距离处的宇宙特性。FRB的弥散量度，再加上其宿主星系的红移，最近就可以直接测量出宇宙中重子的含量，并且有可能直接限制“缺失的重子”的位置。最初的结果与ΛCDM对重子的宇宙密度的期望是一致的，并且为银河系周围非常扩散的星系间媒质（IGM）和绕星系媒质（CGM）的性质提供了第一个约束。FRB是唯一已知的河外源，它的致密性足以表现出衍射闪烁，此外还显示出典型尾巴，这些尾巴是在湍流介质中散射的典型特征。这将使我们能够探测周向介质，主星系ISM /光晕，沿路径的中间光晕以及IGM的湍流特性。哈勃常数和暗能量参数的测量w可以用FRB制成，但需要非常大量的局部FRB样本（>${10}^3$），以使其自身有效-最好将它们与其他独立调查结合起来以改善约束条件。电离事件（例如He ii）在弥散量度-红移关系中留下了特征，并且如果在这些时间之前存在FRB，则它们可用于探测电离时代，尽管不仅仅如此。${10}^3$ 需要本地化的FRB。