Photometric redshifts are essential in studies of both galaxy evolution and cosmology, as they enable analyses of objects too numerous or faint for spectroscopy. The Rubin Observatory, Euclid, and Roman Space Telescope will soon provide a new generation of imaging surveys with unprecedented area coverage, wavelength range, and depth. To take full advantage of these data sets, further progress in photometric redshift methods is needed. In this review, we focus on the greatest common challenges and prospects for improvement in applications of photometric redshifts to the next generation of surveys: ▪ Gains in performance (i.e., the precision of redshift estimates for individual galaxies) could greatly enhance studies of galaxy evolution and some probes of cosmology. ▪ Improvements in characterization (i.e., the accurate recovery of redshift distributions of galaxies in the presence of uncertainty on individual redshifts) are urgently needed for cosmological measurements with next-generation surveys.To achieve both of these goals, improvements in the scope and treatment of the samples of spectroscopic redshifts that make high-fidelity photometric redshifts possible will also be needed. For the full potential of the next generation of surveys to be reached, the characterization of redshift distributions must improve by roughly an order of magnitude compared with the current state of the art, requiring progress on a wide variety of fronts. We conclude by presenting a speculative evaluation of how photometric redshift methods and the collection of the necessary spectroscopic samples may improve by the time near-future surveys are completed.

中文翻译：

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用于下一代测量的光度红移


光度红移在星系演化和宇宙学研究中都是必不可少的，因为它们能够分析光谱学无法分析太多或太暗的天体。鲁宾天文台、欧几里得和罗马太空望远镜将很快提供新一代成像巡天，具有前所未有的区域覆盖范围、波长范围和深度。为了充分利用这些数据集，需要进一步发展光度红移方法。在这篇综述中，我们重点讨论了光度红移应用于下一代巡天的最大常见挑战和改进前景：▪性能的提高（即单个星系的红移估计精度）可以大大加强星系演化的研究和一些宇宙学的探测。▪ 对于下一代巡天宇宙学测量，迫切需要改进表征（即在单个红移存在不确定性的情况下准确恢复星系的红移分布）。为了实现这两个目标，还需要改进光谱红移样品的范围和处理，使高保真光度红移成为可能。为了充分发挥下一代勘测的潜力，与当前技术水平相比，红移分布的表征必须提高大约一个数量级，这需要在各个方面取得进展。最后，我们提出了一个推测性的评估，即在不久的将来完成调查时，光度红移方法和必要光谱样本的收集可能会如何改进。