论文标题

本地组和类似本地组的光环对的电离时间

Reionization time of the Local Group and Local-Group-like halo pairs

论文作者

Sorce, Jenny G., Ocvirk, Pierre, Aubert, Dominique, Gottloeber, Stefan, Shapiro, Paul R., Dawoodbhoy, Taha, Yepes, Gustavo, Ahn, Kyungjin, Iliev, Ilian T., Lewis, Joseph S. W.

论文摘要

斑点的宇宙电离导致整个宇宙的电离紫外线背景异步上升。后者可能在当今的观察中可以看到可见的烙印。基于数值的一些研究表明,当今的电离时间与过度繁殖与物体质量之间的相关性。为了从研究中清除质量,因为这可能不是唯一的重要参数,因此本文仅着眼于与银河系相同质量范围内的配对光环的性质。为此,它使用Codaii,这是当地宇宙的完全耦合的辐射流体动力学模拟。该模拟还具有代表本地组的光环对,除其他对外,共享相似的质量,质量比,距离分离和隔离标准,但在其他环境中,以及在同一质量范围内的孤立晕圈。对配对的光环电离历史的研究揭示了广泛的多样性,尽管鉴于我们的电离模型,但始终内外。在此模型中,近距离倾向于同时进行封闭的光晕,但在一对中并没有使其较早的时间进行平均电源。唯一的显着趋势是在对的Z = 0和它们的平均电源时间之间:对总能量最小的对(绑定)的对比其他能量(未结合)提前50 MYR。最重要的是,这项研究揭示了与当地群体相似的光环对经历的各种电离历史的种类,远非平均一个。在我们的模型中,平均为660 +/- 4 MYR(Z〜8.25,而7.87 +/- 0.02)平均为625 MYR。

Patchy cosmic reionization resulted in the ionizing UV background asynchronous rise across the Universe. The latter might have left imprints visible in present day observations. Several numerical simulation-based studies show correlations between reionization time and overdensities and object masses today. To remove the mass from the study, as it may not be the sole important parameter, this paper focuses solely on the properties of paired halos within the same mass range as the Milky Way. For this purpose, it uses CoDaII, a fully-coupled radiation hydrodynamics reionization simulation of the local Universe. This simulation holds a halo pair representing the Local Group, in addition to other pairs, sharing similar mass, mass ratio, distance separation and isolation criteria but in other environments, alongside isolated halos within the same mass range. Investigations of the paired halo reionization histories reveal a wide diversity although always inside-out given our reionization model. Within this model, halos in a close pair tend to be reionized at the same time but being in a pair does not bring to an earlier time their mean reionization. The only significant trend is found between the total energy at z = 0 of the pairs and their mean reionization time: pairs with the smallest total energy (bound) are reionized up to 50 Myr earlier than others (unbound). Above all, this study reveals the variety of reionization histories undergone by halo pairs similar to the Local Group, that of the Local Group being far from an average one. In our model, its reionization time is ~625 Myr against 660+/-4 Myr (z~8.25 against 7.87+/-0.02) on average.

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