文章基本信息

标题：Photometric Redshifts with the LSST. II. The Impact of Near-infrared and Near-ultraviolet Photometry
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作者：Melissa L.Graham ; Andrew J.Connolly ; Winnie Wang 等
期刊名称：The Astronomical journal
印刷版ISSN：0004-6256
电子版ISSN：1538-3881
出版年度：2020
卷号：159
期号：6
页码：3582-3601
DOI：10.3847/1538-3881/ab8a43
语种：English
出版社：American Institute of Physics
摘要：Accurate photometric redshift (photo-z) estimates are essential to the cosmological science goals of the Vera C.Rubin Observatory Legacy Survey of Space and Time (LSST).In this work, we use simulated photometry for mock galaxy catalogs to explore how LSST photo-z estimates can be improved by the addition of near-infrared (NIR) and/or ultraviolet (UV) photometry from the Euclid, Wide-Field InfrarRed Survey Telescope (WFIRST), and/or Cosmological Advanced Survey Telescope for Optical and ultraviolet Research (CASTOR) space telescopes.Generally, we find that deeper optical photometry can reduce the standard deviation of the photo-z estimates more than adding NIR or UV filters but that additional filters are the only way to significantly lower the fraction of galaxies with catastrophically under- or overestimated photo-z.For Euclid, we find that the addition of JH 5σ photometric detections can reduce the standard deviation for galaxies with z > 1 (z > 0.3) by ~20% (~10%), and the fraction of outliers by ~40% (~25%).For WFIRST, we show how the addition of deep YJHK photometry could reduce the standard deviation by gsim50% at z > 1.5 and drastically reduce the fraction of outliers to just ~2% overall.For CASTOR, we find that the addition of its UV- and u-band photometry could reduce the standard deviation by ~30% and the fraction of outliers by ~50% for galaxies with z < 0.5.We also evaluate the photo-z results within sky areas that overlap with both the NIR and UV surveys and when spectroscopic training sets built from the surveys' small-area deep fields are used.
关键词：Cosmology;Galaxy photometry;Multi-color photometry;Sky surveys