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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用于下一代巡天的光度红移

光度红移在星系演化和宇宙学研究中至关重要，因为它们可以分析数量过多或微弱而无法进行光谱分析的物体。鲁宾天文台、欧几里得和罗马太空望远镜很快将提供新一代成像勘测，其区域覆盖范围、波长范围和深度都是前所未有的。为了充分利用这些数据集，需要在光度红移方法方面取得进一步进展。在这篇综述中，我们重点关注光度红移在下一代巡天应用中最常见的挑战和改进前景： ▪ 性能提升（即单个星系红移估计的精度）可以极大地增强对星系演化的研究以及宇宙学的一些探索。 ▪ 下一代巡天宇宙学测量迫切需要改进表征（即，在个体红移存在不确定性的情况下准确恢复星系红移分布）。为了实现这两个目标，需要改进观测范围和处理方法。还需要使高保真光度红移成为可能的光谱红移样本。为了充分发挥下一代调查的潜力，红移分布的表征必须比当前技术水平提高大约一个数量级，需要在各个方面取得进展。最后，我们对光度红移方法和必要的光谱样本的收集在不久的将来调查完成时可能如何改进进行了推测性评估。