Seen and unseen: bursty star formation and its implications for observations of high-redshift galaxies with JWST
Seen and unseen: bursty star formation and its implications for observations of high-redshift galaxies with JWST
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可见与不可见：爆发式恒星形成及其对 JWST 观测高红移星系的影响
DOI：
10.1093/mnras/stad2902
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发表时间：
2023
影响因子：
4.8
通讯作者：
Shen, Xuejian
中科院分区：
文献类型：
--
作者：
Sun, Guochao;Faucher-Giguère, Claude-André;Hayward, Christopher C.;Shen, Xuejian
观测和模拟都显示了强有力的证据，证明在低质量和/或高红移星系中存在高度时变的星星形成，这具有重要的观测意义，因为高红移星系样本是静止紫外线（rest-UV）选择的，因此对最近的星星形成特别敏感。利用一套宇宙学“放大”模拟atz> 5的反馈在现实环境中的项目，我们研究的影响，突发星星的形成历史的观测高红移星系与JWST。我们描述了星系的可观测性如何依赖于星星的形成历史。我们还调查了选择效应，由于突发星星形成的物理性质测量，如气体分数，特定的星星形成率，和金属丰度。我们发现，由于星星形成率的变化，在调查的极限通量附近的星系的可观测性是高度依赖于时间的：作为星星形成率波动，相同的星系振荡和可观测的样本。JWST/NIRCam巡天观测到的可观测分数为107.7和108.5，达到极限星等，代表了JADES和CEERS等巡天。JWST可探测的星系在巡天极限附近往往具有爆发阶段星系的特性：平均来说，它们的寒冷程度是普通的2.5倍，致密的气体部分和20倍以上的特定星星形成率在一个给定的恒星质量比星系低于静止紫外线检测阈值。我们的研究代表了在研究高红移星系性质时，由于爆发性星星形成而产生的选择效应和相关偏差的量化的第一步。
Both observations and simulations have shown strong evidence for highly time-variable star formation in low-mass and/or high-redshift galaxies, which has important observational implications because high-redshift galaxy samples are rest-ultraviolet (rest-UV) selected and therefore particularly sensitive to the recent star formation. Using a suite of cosmological ‘zoom-in’ simulations atz> 5 from the Feedback in Realistic Environments project, we examine the implications of bursty star formation histories for observations of high-redshift galaxies withJWST. We characterize how the galaxy observability depends on the star formation history. We also investigate selection effects due to bursty star formation on the physical properties measured, such as the gas fraction, specific star formation rate, and metallicity. We find the observability to be highly time-dependent for galaxies near the survey’s limiting flux due to the star formation rate variability: as the star formation rate fluctuates, the same galaxy oscillates in and out of the observable sample. The observable fractionatz∼ 7 andM⋆∼ 108.5–for aJWST/NIRCam survey reaching a limiting magnitude of, representative of surveys such as JADES and CEERS.JWST-detectable galaxies near the survey limit tend to have properties characteristic of galaxies in the bursty phase: on average, they show approximately 2.5 times higher cold, dense gas fractions and 20 times higher specific star formation rates at a given stellar mass than galaxies below the rest-UV detection threshold. Our study represents a first step in quantifying selection effects and the associated biases due to bursty star formation in studying high-redshift galaxy properties.