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arXiv 1902.01427astro-ph.GA
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星系团中红旋涡星系运动学的新限制

New constraints on red-spiral galaxies from their kinematics in clusters of galaxies

Akinari Hamabata, Taira Oogi, Masamune Oguri, Takahiro Nishimichi, Masahiro Nagashima

摘要:

星系和它们的宿主星系团之间的成对视线速度的分布是根据星系的颜色和形态分离的。我们研究了红旋涡星系的速度分布,它代表了星系团中一个罕见的群体。在93%置信水平下,我们发现红旋涡星系和星系团之间的视向速度$v_{\rm{los}}$的概率分布函数在$v_{\rm{los}} = 0$处有一个凹陷,这是一个非常奇怪的特征。为了理解它的起源,我们利用宇宙学$N$体模拟,在三维空间中构造了星系团周围星系的相空间分布模型。我们采用了一个两个组件的模型,包括落入组件,这对应于星系,现在落入星系团,和回溅组件,这对应于星系的第一个(或更多)轨道后,落入星系团。我们发现,我们可以重现的视线速度的红螺旋星系的分布与下降一个非常简单的假设,即红螺旋星系主要居住在下降组件,无论其空间分布的函数形式的选择。我们的结果限制了红旋涡星系的猝灭时间尺度为几个Gyrs,和半径的形态转换是有效的$r \sim 0.2 h^{-1} \rm{Mpc}$。

英文摘要:

The distributions of the pairwise line-of-sight velocity between galaxies and their host clusters are segregated according to the galaxy's colour and morphology. We investigate the velocity distribution of red-spiral galaxies, which represents a rare population within galaxy clusters. We find that the probability distribution function of the pairwise line-of-sight velocity $v_{\rm{los}}$ between red-spiral galaxies and galaxy clusters has a dip at $v_{\rm{los}} = 0$, which is a very odd feature, at 93\% confidence level. To understand its origin, we construct a model of the phase space distribution of galaxies surrounding galaxy clusters in three-dimensional space by using cosmological $N$-body simulations. We adopt a two component model that consists of the infall component, which corresponds to galaxies that are now falling into galaxy clusters, and the splashback component, which corresponds to galaxies that are on their first (or more) orbit after falling into galaxy clusters. We find that we can reproduce the distribution of the line-of-sight velocity of red-spiral galaxies with the dip with a very simple assumption that red-spiral galaxies reside predominantly in the infall component, regardless of the choice of the functional form of their spatial distribution. Our results constrain the quenching timescale of red-spiral galaxies to a few Gyrs, and the radius where the morphological transformation is effective as $r \sim 0.2 h^{-1} \rm{Mpc}$.

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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