LEVERAGING 3D-HST GRISM REDSHIFTS TO QUANTIFY PHOTOMETRIC REDSHIFT PERFORMANCE
Wake, David A.
Brammer, Gabriel B.
Dokkum, Pieter G. van
Momcheva, Ivelina G.
Nelson, Erica J.
Quadri, Ryan F.
Skelton, Rosalind E.
Weiner, Benjamin J.
Whitaker, Katherine E.
AffiliationUniv Arizona, Dept Astron, Steward Observ
MetadataShow full item record
PublisherIOP PUBLISHING LTD
CitationLEVERAGING 3D-HST GRISM REDSHIFTS TO QUANTIFY PHOTOMETRIC REDSHIFT PERFORMANCE 2016, 822 (1):30 The Astrophysical Journal
JournalThe Astrophysical Journal
Rights© 2016. The American Astronomical Society. All rights reserved.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at email@example.com.
AbstractWe present a study of photometric redshift accuracy in the 3D-HST photometric catalogs, using 3D-HST grism redshifts to quantify and dissect trends in redshift accuracy for galaxies brighter than JH(IR) > 24 with an unprecedented and representative high-redshift galaxy sample. We find an average scatter of 0.0197 +/- 0.0003(1 + z) in the Skelton et al. photometric redshifts. Photometric redshift accuracy decreases with magnitude and redshift, but does not vary monotonically with color or stellar mass. The 1 sigma scatter lies between 0.01 and 0.03 (1 + z) for galaxies of all masses and colors below z. <. 2.5 (for JH(IR) < 24), with the exception of a population of very red (U - V > 2), dusty star-forming galaxies for which the scatter increases to similar to 0.1 (1+ z). We find that photometric redshifts depend significantly on galaxy size; the largest galaxies at fixed magnitude have photo-zs with up to similar to 30% more scatter and similar to 5 times the outlier rate. Although the overall photometric redshift accuracy for quiescent galaxies is better than that for star-forming galaxies, scatter depends more strongly on magnitude and redshift than on galaxy type. We verify these trends using the redshift distributions of close pairs and extend the analysis to fainter objects, where photometric redshift errors further increase to similar to 0.046 (1 + z) at H-F160W = 26. We demonstrate that photometric redshift accuracy is strongly filter dependent and quantify the contribution of multiple filter combinations. We evaluate the widths of redshift probability distribution functions and find that error estimates are underestimated by a factor of similar to 1.1 - 1.6, but that uniformly broadening the distribution does not adequately account for fitting outliers. Finally, we suggest possible applications of these data in planning for current and future surveys and simulate photometric redshift performance in the Large Synoptic Survey Telescope, Dark Energy Survey (DES), and combined DES and Vista Hemisphere surveys.
VersionFinal published version
SponsorsNASA through Hubble Fellowship - Space Telescope Science Institute [HF-51318, HF2-51368]; NASA [NAS5-26555]; 3D-HST Treasury Program [GO 12177, 12328]