论文标题
分位数作为21厘米图像中非高斯性的鲁棒探针
Quantiles as Robust Probes of Non-Gaussianity in 21-cm Images
论文作者
论文摘要
首先形成的恒星和星系的早期时代是宇宙中最令人兴奋的尚未开发的时代之一。一项重大的研究工作重点是用21 cm的氢谱图探测这个时代。尽管大多数研究都集中在21 cm功率谱或天空平均全球信号等统计数据上，但还有其他方法可以分析层析成像21厘米地图，这可能会导致新的见解。我们建议基于分位数的统计数据作为探测21 cm信号非高西度性的一种方法。我们表明，它们可以特别用于探测温度分布的方差，偏度和峰度，但比这些标准统计数据更灵活，更健壮。我们在一系列可能的天体物理模型上测试了这些统计数据，包括不同的银河光环质量，恒星形成效率和X射线加热源的光谱，以及具有过量早期无线电背景的外来模型。我们根据平方公里阵列（SKA）的预期模拟数据，我们得出结论，可以将这些统计数据测量到高于20以上的红移，并提供了一种有希望的统计方法来探测早期宇宙历史。
The early epoch in which the first stars and galaxies formed is among the most exciting unexplored eras of the Universe. A major research effort focuses on probing this era with the 21-cm spectral line of hydrogen. While most research focused on statistics like the 21-cm power spectrum or the sky-averaged global signal, there are other ways to analyze tomographic 21-cm maps, which may lead to novel insights. We suggest statistics based on quantiles as a method to probe non-Gaussianities of the 21-cm signal. We show that they can be used in particular to probe the variance, skewness, and kurtosis of the temperature distribution, but are more flexible and robust than these standard statistics. We test these statistics on a range of possible astrophysical models, including different galactic halo masses, star-formation efficiencies, and spectra of the X-ray heating sources, plus an exotic model with an excess early radio background. Simulating data with angular resolution and thermal noise as expected for the Square Kilometre Array (SKA), we conclude that these statistics can be measured out to redshifts above 20 and offer a promising statistical method for probing early cosmic history.
