论文标题

从第一个JWST/NIRCAM字段z> 8的紫外光度密度在z> 8中产生:早期数据集的局限性和对光谱的需求

UV Luminosity Density Results at z>8 from the First JWST/NIRCam Fields: Limitations of Early Data Sets and the Need for Spectroscopy

论文作者

Bouwens, Rychard, Illingworth, Garth, Oesch, Pascal, Stefanon, Mauro, Naidu, Rohan, van Leeuwen, Ivana, Magee, Dan

论文摘要

我们使用了三个最研究的JWST/NIRCAM数据集,SMACS0723,玻璃平行和CEORS领域,并在Z〜17到Z〜8的紫外线光度和SFR密度从Z〜17到Z〜8设置了约束。我们首先使用最新校准对这些数据集的两个独立减少使用了自己的选择。 18 Z〜8、12 Z〜10、5 Z〜13和1 Z〜17候选星系在我们的主要减少的这些磁场上被鉴定出来,在我们的次级减少中,候选人数量相似。然后,我们使用这两种降低,应用定量歧视者,将在这些领域中报告的Z> 〜8候选物的完整集隔离为三种不同的样本,分别为``稳定性''''''solid,'''''''''''''''''''''''''''和`'可能。然后,使用所有这些样品,我们得出UV LF和亮度密度为$ z \ geq8 $,发现实质性差异。例如,包括整个文献中的``固体''和``可能的''z> 〜12个候选者,我们发现紫外线密度〜7倍,比依靠``稳定''''''''''''和〜20x高约20倍。这些结果表明紫外线LF的演变和z> 〜8处的光度密度仍然非常不确定,这强调了光谱的需求和更深的Nircam+光学成像以获得可靠的结果。但是,即使采用非常保守的``强大''选择方法,无论是从我们自己和其他研究中的选择方法,我们还是发现使用恒定的恒星形成效率模型的发光(M(UV)<-19)星系的光度密度比可轻松实现的亮度密度大于2x,类似于其他早期JWST结果。

We have derived luminosity functions, and set constraints on the UV luminosity and SFR density from z~17 to z~8, using the three most-studied JWST/NIRCam data sets, the SMACS0723, GLASS Parallel, and CEERS fields. We first used our own selections on two independent reductions of these datasets using the latest calibrations. 18 z~8, 12 z~10, 5 z~13, and 1 z~17 candidate galaxies are identified over these fields in our primary reductions, with a similar number of candidates in our secondary reductions. We then use these two reductions, applying a quantitative discriminator, to segregate the full set of z>~8 candidates reported over these fields from the literature, into three different samples, ``robust,'' ``solid,'' and ``possible''. Using all of these samples we then derive UV LF and luminosity density results at $z\geq8$, finding substantial differences. For example, including the full set of ``solid'' and ``possible'' z>~12 candidates from the literature, we find UV luminosity densities which are ~7x and ~20x higher than relying on the ``robust'' candidates alone. These results indicate the evolution of the UV LF and luminosity densities at z>~8 is still extremely uncertain, emphasizing the need for spectroscopy and deeper NIRCam+optical imaging to obtain reliable results. Nonetheless, even with the very conservative ``robust'' approach to selections, both from our own and those of other studies, we find the luminosity density from luminous (M(UV)<-19) galaxies to be ~2x larger than is easily achievable using constant star-formation efficiency models, similar to what other early JWST results have suggested.

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