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arXiv 1503.01110astro-ph.GA
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用Renaissance模拟探讨最早银河系的紫外光度函数

Probing The Ultraviolet Luminosity Function of the Earliest Galaxies with the Renaissance Simulations

Brian W. O'Shea, John H. Wise, Hao Xu, Michael L. Norman

摘要:

在本文中,我们提出的第一个结果,从文艺复兴时期的模拟,一套非常高的分辨率和物理丰富的AMR计算高红移星系形成的蓝水超级计算机上进行。这些模拟包含了$z \sim 25-8$上数百个分辨率很好的星系,并做出了几个新颖的、可检验的预测。最关键的是,我们模拟的星系的紫外线光度函数是一致的高Z星系人口的光度函数(M $_{1600} \leq -17$)的明亮端的观察,但在较低的光度基本上是平坦的,而不是急剧上升,如已推断的Schechter函数适合高Z观测,并有一个明确定义的紫外线光度下限。光度函数的这种行为是由于两个因素:(i)在我们模拟的星系群中,恒星形成速率对晕维里质量的强烈依赖,低质量的晕具有系统性的较低恒星形成速率,因此具有较低的紫外光度;和(ii)维里质量低于$\simeq 2 \times 10^8$ M $_\odot$的晕并不普遍包含恒星,在$\simeq 7 \times 10^6$ M $_\odot$处,包含恒星的晕的比例下降到零。最后,我们表明,我们模拟的星系中最亮的可能是可见的当前和未来的超深空基调查,特别是如果选择透镜区域进行观测。

英文摘要:

In this paper, we present the first results from the Renaissance Simulations, a suite of extremely high-resolution and physics-rich AMR calculations of high redshift galaxy formation performed on the Blue Waters supercomputer. These simulations contain hundreds of well-resolved galaxies at $z \sim 25-8$, and make several novel, testable predictions. Most critically, we show that the ultraviolet luminosity function of our simulated galaxies is consistent with observations of high-z galaxy populations at the bright end of the luminosity function (M$_{1600} \leq -17$), but at lower luminosities is essentially flat rather than rising steeply, as has been inferred by Schechter function fits to high-z observations, and has a clearly-defined lower limit in UV luminosity. This behavior of the luminosity function is due to two factors: (i) the strong dependence of the star formation rate on halo virial mass in our simulated galaxy population, with lower-mass halos having systematically lower star formation rates and thus lower UV luminosities; and (ii) the fact that halos with virial masses below $\simeq 2 \times 10^8$ M$_\odot$ do not universally contain stars, with the fraction of halos containing stars dropping to zero at $\simeq 7 \times 10^6$ M$_\odot$. Finally, we show that the brightest of our simulated galaxies may be visible to current and future ultra-deep space-based surveys, particularly if lensed regions are chosen for observation.

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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