Hybrid photometric redshifts for sources in the COSMOS and XMM-LSS fields. Issue 3 (15th April 2022)

• Record Type: Journal Article
• Authors: Hatfield, P W; Jarvis, M J; Adams, N; Bowler, R A A; Häußler, B; Duncan, K J
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 513:Issue 3(2022)
• Page Start: 3719
• Page End: 3733
• Publication Date: 2022-04-15
• Subjects: techniques: photometric -- surveys -- galaxies: distances and redshifts; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stac1042
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: In this paper, we present photometric redshifts for 2.7 million galaxies in the XMM-LSS and COSMOS fields, both with rich optical and near-infrared data from VISTA and HyperSuprimeCam. Both template fitting (using galaxy and active galactic nuclei templates within LePhare ) and machine learning (using gp z) methods are run on the aperture photometry of sources selected in the K s -band. The resulting predictions are then combined using a Hierarchical Bayesian model, to produce consensus photometric redshift point estimates and probability distribution functions that outperform each method individually. Our point estimates have a root mean square error of ∼0.08–0.09, and an outlier fraction of ∼3–4 percent when compared to spectroscopic redshifts. We also compare our results to the COSMOS2020 photometric redshifts, which contain fewer sources, but had access to a larger number of bands and greater wavelength coverage, finding that comparable photo- z quality can be achieved (for bright and intermediate luminosity sources where a direct comparison can be made). Our resulting redshifts represent the most accurate set of photometric redshifts (for a catalogue this large) for these deep multisquare degree multiwavelength fields to date.