arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2009.03093astro-ph.CO
收藏

开放再电离:再电离时期的定量形态学及其与宇宙密度场的联系

Opening Reionization: Quantitative Morphology of the Epoch of Reionization and Its Connection to the Cosmic Density Field

Philipp Busch, Marius B. Eide, B. Ciardi, Koki Kakiichi

摘要:

我们介绍了一个通用的和空间分辨的二进制字段的形态特征,植根于数学形态学的开放变换。随后,我们将其应用到阈值电离场的模拟宇宙再电离和研究电离区的形态。我们发现,一个电离体积元素通常驻留在一个电离区域半径$\sim8\,h^{-1}\mathrm{cMpc}$在中点的再电离($z\approx7.5$),并遵循气泡的尺寸分布,甚至超出重叠阶段。我们发现,渗透的完全电离的组件集时,25%的宇宙是电离的,由此产生的无限集群包含所有电离区域以上$\sim8\,h^{-1}\mathrm{cMpc}$。我们还量化了不同半径的电离区域相对于物质的聚类,并在小尺度上检测重叠阶段中超级气泡的形成。在大尺度上,我们量化了不同大小的电离和中性区域中心的偏置值,不仅表明在再电离的高点最大的可以达到$b\approx 30$,而且早期的小电离区域与物质正相关,大的中性区域和晚期的小电离区域与物质严重反偏置,下降到$b\lesssim-20$。

英文摘要:

We introduce a versatile and spatially resolved morphological characterisation of binary fields, rooted in the opening transform of mathematical morphology. We subsequently apply it to the thresholded ionization field in simulations of cosmic reionization and study the morphology of ionized regions. We find that an ionized volume element typically resides in an ionized region with radius $\sim8\,h^{-1}\mathrm{cMpc}$ at the midpoint of reionization ($z\approx7.5$) and follow the bubble size distribution even beyond the overlap phase. We find that percolation of the fully ionized component sets in when 25% of the universe is ionized and that the resulting infinite cluster incorporates all ionized regions above $\sim8\,h^{-1}\mathrm{cMpc}$. We also quantify the clustering of ionized regions of varying radius with respect to matter and on small scales detect the formation of superbubbles in the overlap phase. On large scales we quantify the bias values of the centres of ionized and neutral regions of different sizes and not only show that the largest ones at the high-point of reionization can reach $b\approx 30$, but also that early small ionized regions are positively correlated with matter and large neutral regions and late small ionized regions are heavily anti-biased with respect to matter, down to $b\lesssim-20$.

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。

↑