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Selection of Massive Evolved Galaxies at 3 ≤ z ≤ 4.5 in the CANDELS Fields
The Astrophysical Journal ( IF 4.8 ) Pub Date : 2020-07-01 , DOI: 10.3847/1538-4357/ab96c5
Abtin Shahidi 1 , Bahram Mobasher 1 , Hooshang Nayyeri 2 , Shoubaneh Hemmati 3 , Tommy Wiklind 4 , Nima Chartab 1 , Mark Dickinson 5 , Steven L Finkelstein 6 , Camilla Pacifici 7 , Casey Papovich 8 , Henry C. Ferguson 7 , Adriano Fontana 9 , Mauro Giavalisco 10 , Anton Koekemoer 7 , Jeffery Newman 11 , Zahra Sattari 1 , Rachel Somerville 12, 13
Affiliation  

Using the CANDELS photometric catalogs for the HST/ACS and WFC3, we identified massive evolved galaxies at $3 < z < 4.5$, employing three different selection methods. We find the comoving number density of these objects to be $\sim 2 \times 10^{-5}$ and $8 \times 10^{-6}Mpc^{-3}$ after correction for completeness for two redshift bins centered at $z=3.4, 4.7$. We quantify a measure of how much confidence we should have for each candidate galaxy from different selections and what are the conservative error estimates propagated into our selection. Then we compare the evolution of the corresponding number densities and their stellar mass density with numerical simulations, semi-analytical models, and previous observational estimates, which shows slight tension at higher redshifts as the models tend to underestimate the number and mass densities. By estimating the average halo masses of the candidates ($M_h \approx 4.2, 1.9, 1.3 \times 10^{12} M_\odot$ for redshift bins centered at $z=3.4, 4.1, 4.7$), we find them to be consistent with halos that were efficient in turning baryons to stars and were relatively immune to the feedback effects and on the verge of transition into hot-mode accretion. This can suggest the relative cosmological starvation of the cold gas followed by an overconsumption phase in which the galaxy consumes the available cold gas rapidly as one of the possible drivers for the quenching of the massive evolved population at high redshift.

中文翻译:

在 CANDELS 场中选择 3 ≤ z ≤ 4.5 处的大质量演化星系

使用 HST/ACS 和 WFC3 的 CANDELS 光度目录,我们使用三种不同的选择方法确定了 $3 < z < 4.5 $ 的大规模演化星系。我们发现这些物体的协移动数密度为 $\sim 2 \times 10^{-5}$ 和 $8 \times 10^{-6}Mpc^{-3}$ 在对两个居中的红移箱进行完整性校正后在 $z=3.4, 4.7$。我们量化了对来自不同选择的每个候选星系应该有多少置信度的度量,以及传播到我们选择中的保守误差估计是多少。然后,我们将相应的数密度及其恒星质量密度的演变与数值模拟、半解析模型和先前的观测估计进行比较,由于模型倾向于低估数量和质量密度,因此在较高的红移处显示出轻微的张力。通过估计候选者的平均晕质量($M_h \approx 4.2, 1.9, 1.3 \times 10^{12} M_\odot$ for redshift bins 以$z=3.4, 4.1, 4.7$为中心),我们发现他们与能够有效地将重子变成恒星并且对反馈效应相对免疫并且处于过渡到热模式吸积的边缘的光晕一致。这可以表明冷气体的相对宇宙学饥饿,然后是过度消耗阶段,在该阶段中,星系迅速消耗可用的冷气体,这是在高红移时大量演化种群淬灭的可能驱动因素之一。我们发现它们与能够有效地将重子转化为恒星的晕相一致,并且相对不受反馈效应的影响,并且处于过渡到热模式吸积的边缘。这可以表明冷气体的相对宇宙学饥饿,然后是过度消耗阶段,在该阶段中,星系迅速消耗可用的冷气体,这是在高红移时大量演化种群淬灭的可能驱动因素之一。我们发现它们与能够有效地将重子转化为恒星的晕相一致,并且相对不受反馈效应的影响,并且处于过渡到热模式吸积的边缘。这可以表明冷气体的相对宇宙学饥饿,然后是过度消耗阶段,在该阶段中,星系迅速消耗可用的冷气体,这是在高红移时大量演化种群淬灭的可能驱动因素之一。
更新日期:2020-07-01
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