论文标题

是什么决定了星系的最大恒星表面密度?

What determines the maximum stellar surface density of galaxies?

论文作者

Ling, Chih-Teng, Hashimoto, Tetsuya, Goto, Tomotsugu, Lu, Ting-Yi, On, Alvina Y. L., Santos, Daryl Joe D., Hsiao, Tiger Y. -Y., Ho, Simon C. -C.

论文摘要

从观察上讲,据报道,宇宙中最浓的恒星系统不超过最大恒星表面密度,$σ^{\ max} _ {*} $ = $ 3 \ times10^5 $ m $ _ {\ odot} $ pc $ pc $ pc $^{ - 2} $,整个宽阔的物理规模,来自宽阔的物理规模,来自Galax rang rang rang rang rang rang rang rang galaxy to gallaxy callaxy。这表明存在一个基本物理学,可以调节恒星形成和恒星密度。但是,确定最大限制的因素尚不清楚。在这项研究中,我们表明,星系的$σ^{\ max} _ {*} $不是以前报告的常数,而是实际上取决于恒星质量。我们从Sloan Digital Sky Survey Data Release 12 at $ z = 0.01-0.5 $中选择Galaxy样本。与理论模型预测的恒定最大值相反,$σ^{\ max} _ {*} $在很大程度上取决于恒星质量,尤其是对于具有$ \ sim10^{10} $ m $ _ $ _ {\ odot} $的较小的大型星系。我们还发现,大多数高$σ_ {*} $星系显示出红色和低星形速率。这些星系可能到达$σ^{\ max} _ {*} $,这是由于星系从蓝色星形形成到红色静止的星系进化而导致的。 $σ^{\ max} _ {*} $的恒星质量依赖关系的一种可能解释是恒星反馈的质量依赖效率。在较浅的重力电位中,恒星反馈可以相对效率更高,在恒星系统达到高恒星密度之前,恒星迅速终止了恒星。

Observationally, it has been reported that the densest stellar system in the Universe does not exceed a maximum stellar surface density, $Σ^{\max}_{*}$ = $3\times10^5$M$_{\odot}$pc$^{-2}$, throughout a wide physical scale ranging from star cluster to galaxy. This suggests there exists a fundamental physics which regulates the star formation and stellar density. However, factors that determine this maximum limit are not clear. In this study, we show that $Σ^{\max}_{*}$ of galaxies is not a constant as previous work reported, but actually depends on the stellar mass. We select galaxy sample from the Sloan Digital Sky Survey Data Release 12 at $z=0.01-0.5$. In contrast to a constant maximum predicted by theoretical models, $Σ^{\max}_{*}$ strongly depends on stellar mass especially for less massive galaxies with $\sim10^{10}$M$_{\odot}$. We also found that a majority of high-$Σ_{*}$ galaxies show red colours and low star-formation rates. These galaxies probably reach the $Σ^{\max}_{*}$ as a consequence of the galaxy evolution from blue star forming to red quiescent by quenching star formation. One possible explanation of the stellar-mass dependency of $Σ^{\max}_{*}$ is a mass dependent efficiency of stellar feedback. The stellar feedback could be relatively more efficient in a shallower gravitational potential, which terminates star formation quickly before the stellar system reaches a high stellar density.

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