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arXiv 0901.2898astro-ph.GAastro-ph.CO
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早期宇宙中静止大质量星系的比例

The Fraction of Quiescent Massive Galaxies in the Early Universe

A. Fontana, P. Santini, A. Grazian, L. Pentericci, F. Fiore, M. Castellano, E. Giallongo, N. Menci, S. Salimbeni, S. Cristiani, M. Nonino, E. Vanzella

摘要:

目的:这项工作的目的是收集一个完整的,质量-选择的样本的星系非常低的特定的恒星形成率,与最近的理论模型的预测进行比较。方法:我们使用的24/K的流量比,补充SED拟合完整的0.35-8.0妈妈的光谱分布,选择静止星系从z~0.4到z~4的GOODS-MUSIC样本。我们的观测选择可以转化为特定恒星形成率SFR/M_* 的阈值,可用于与理论预测进行比较。结果如下:我们发现,在静止部分随红移而下降的框架下,在z~4范围内,有15-20%的大质量星系具有很低的比恒星形成率,其中包括一个SFR/M_*<10^{-11}/yr的“Red&Dead”星系的尾部。最近的理论模型在很大程度上不同的预测比例的星系非常低的特定的恒星形成率,并无法提供一个全球性的匹配我们的数据。

英文摘要:

Aims: The aim of this work is to collect a complete, mass--selected sample of galaxies with very low specific star formation rate, for a comparison with the prediction of recent theoretical models. Method: We use the 24/K flux ratio, complemented by the SED fitting to the full 0.35-8.0 mum spectral distribution, to select quiescent galaxies from z~0.4 to z~4 in the GOODS--MUSIC sample. Our observational selection can be translated into thresholds on the specific star formation rate SFR/M_*, that can be used to compare with the theoretical predictions. Results: We find that, in the framework of the well known global decline of the quiescent fraction with redshift, a non-negligible fraction ~15-20% of massive galaxies with very low specific star formation rate exists up to z~4, including a tail of "Red&Dead" galaxies with SFR/M_*<10^{-11}/yr. Recent theoretical models vary to a large extent in the prediction of the fraction of galaxies with very low specific star formation rates, and are unable to provide a global match to our data.

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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