Title: ΛCDM is still not broken: empirical constraints on the star formation efficiency at z ~ 12-30 Show Chinese title

Title: ΛCDM仍然未被打破：对z ~ 12-30的恒星形成效率的经验限制

Abstract: The James Webb Space Telescope continues to push back the redshift frontier to ever earlier cosmic epochs, with recent announcements of galaxy candidates at redshifts of $15 \lesssim z \lesssim 30$. We leverage the recent GUREFT suite of dissipationless $N$-body simulations, which were designed for interpreting observations in the high redshift Universe, and provide predictions of dark matter halo mass functions and halo growth rates for a state-of-the-art cosmology over a wide range of halo masses from $6 < z< 30$. We combine these results with an empirical framework that maps halo growth rate to galaxy star formation rate and then to rest-frame UV luminosity. We find that even if all of the photometrically selected $15 \lesssim z \lesssim 30$ galaxy candidates are real and actually at these extreme redshifts, there is no fundamental tension with $\Lambda$CDM, nor are exotic explanations required. With stellar light-to-mass ratios similar to those in well-studied lower redshift galaxies, our simple model can account for the observed extreme ultra-high redshift populations with star formation efficiencies that peak at values of 20-65 percent. Bursty star formation, or higher light-to-mass ratios such as are expected for lower metallicity stellar populations or a top-heavy Initial Mass Function, would result in even lower required star formation efficiencies, comparable to values predicted by high resolution numerical simulations of high-surface density star forming clouds. Show Chinese abstract

Abstract: 詹姆斯·韦布空间望远镜持续将红移前沿推至更早的宇宙时代，最近宣布了在红移为$15 \lesssim z \lesssim 30$的星系候选者。 我们利用最近的 GUREFT 无耗散$N$-体模拟套件，这些模拟旨在解释高红移宇宙中的观测结果，并提供了在广泛范围的暗物质晕质量下，针对最先进的宇宙学模型的暗物质晕质量函数和晕增长速率的预测，从$6 < z< 30$开始。 我们将这些结果与一个经验框架相结合，该框架将晕增长速率映射到星系恒星形成率，再映射到静止帧紫外光度。 我们发现，即使所有通过光度选择的$15 \lesssim z \lesssim 30$星系候选者都是真实的并且确实位于这些极端红移处，也不会与$\Lambda$冷暗物质（CDM）产生根本性矛盾，也不需要奇异的解释。 在恒星光度与质量比类似于在低红移星系中广泛研究的星系的情况下，我们的简单模型可以解释观测到的极端超高红移星系群体，其恒星形成效率在 20-65% 的值处达到峰值。 爆发性恒星形成，或更高的光度与质量比，如低金属丰度恒星种群或顶重初始质量函数所预期的那样，会导致更低的所需恒星形成效率，与高分辨率数值模拟的高表面密度恒星形成云预测的数值相当。