The Compilation and Validation of the Spectroscopic Redshift Catalogs for the DESI-COSMOS and DESI-XMMLSS Fields

TL;DR

This paper presents the development, validation, and application of spectroscopic redshift catalogs for the DESI-COSMOS and DESI-XMMLSS fields, including target selection algorithms and multi-catalog photometry for cosmological analyses.

Contribution

It introduces robust spectroscopic redshift criteria, validates them, and provides comprehensive catalogs and target selection algorithms for the DESI fields.

Findings

Reliable classification of galaxies, quasars, and stars below z<1.6.

Provision of matched photometry from multiple imaging surveys.

Demonstration of catalog applications in redshift estimation and cluster studies.

Abstract

Over several dedicated programs that include targets beyond the main cosmological samples, the Dark Energy Spectroscopic Instrument (DESI) collected spectra for 304,970 unique objects in two fields centered on the COSMOS and XMM-LSS fields. In this work, we develop spectroscopic redshift robustness criteria for those spectra, validate these criteria using visual inspection, and provide two custom Value-Added Catalogs with our redshift characterizations. With these criteria, we reliably classify 212,935 galaxies below z < 1.6, 9,713 quasars and 35,222 stars. As a critical element in characterizing the selection function, we provide the description of 70 different algorithms that were used to select these targets from imaging data. To facilitate joint imaging/spectroscopic analyses, we provide row-matched photometry from the Dark Energy Camera, Hyper-Suprime Cam, and public COSMOS2020 photometric catalogs. Finally, we demonstrate example applications of these large catalogs to photometric redshift estimation, cluster finding, and completeness studies.