Projects per year
Abstract
In this paper we present photometric redshift (photo-z)
estimates for the Dark Energy Spectroscopic Instrument (DESI) Legacy
Imaging Surveys, currently the most sensitive optical survey covering
the majority of the extra-galactic sky. Our photo-z methodology
is based on a machine-learning approach, using sparse Gaussian
processes augmented with Gaussian mixture models (GMMs) that allow
regions of parameter space to be identified and trained separately in a
purely data-driven way. The same GMMs are also used to calculate
cost-sensitive learning weights that mitigate biases in the
spectroscopic training sample. By design, this approach aims to produce
reliable and unbiased predictions for all parts of the parameter space
present in wide area surveys. Compared to previous literature estimates
using the same underlying photometry, our photo-zs are significantly less biased and more accurate at z > 1, with negligible loss in precision or reliability for resolved galaxies at z < 1. Our photo-z
estimates offer accurate predictions for rare high-value populations
within the parent sample, including optically selected quasars at the
highest redshifts (z > 6), as well as X-ray or radio
continuum selected populations across a broad range of flux (densities)
and redshift. Deriving photo-z estimates for the full Legacy Imaging Surveys Data Release 8, the catalogues provided in this work offer photo-z estimates predicted to be high quality for ≳ 9 × 108 galaxies over ∼19 400 deg2 and spanning 0 < z ≲ 7, offering one of the most extensive samples of redshift estimates ever produced.
Original language | English |
---|---|
Pages (from-to) | 3662-3683 |
Number of pages | 22 |
Journal | Monthly Notices of the Royal Astronomical Society |
Volume | 512 |
Issue number | 3 |
Early online date | 8 Mar 2022 |
DOIs | |
Publication status | Published - 1 May 2022 |
Keywords / Materials (for Non-textual outputs)
- X-rays: galaxies
- catalogues
- galaxies: distances and redshifts
- quasars: general
- radio continuum: galaxies
Fingerprint
Dive into the research topics of 'All-purpose, all-sky photometric redshifts for the Legacy Imaging Surveys Data Release 8'. Together they form a unique fingerprint.Projects
- 1 Finished
-
HIZRAD: How the monsters were made: the formation of the most massive black holes in the Universe
1/09/20 → 31/08/22
Project: Research