COSMOS2020: A panchromatic view of the Universe to z~10 from two complementary catalogs

The COSMOS field has proven to be one of the cornerstone surveys in extragalactic astronomy. Since our last public catalog in 2015, a wealth of new imaging and spectroscopic data has been collected in COSMOS. We describe the collection, processing, and analysis of the best available imaging data in COSMOS over 39 bands and produce a new reference photometric redshift catalog. Powerful new constraints are made possible from the ultra-deep optical imaging with Hyper Suprime-Cam, UltraVISTA near-infrared Ks imaging at least 1 magnitude deeper than in 2015, and the inclusion of all Spitzer IRAC infrared imaging ever taken on COSMOS. We find significant improvement in our astrometric reference from 2015 by utilizing Gaia DR1. From this reprocessed data, we perform source detection and photometry for 1 million sources across 2 deg2 of the COSMOS field, using both traditional aperture photometric methods and a new profile-fitting photometric measurement tool we have developed. In addition to a detailed comparison of both methods, we report the achievement of sub-percent accuracy in our derived photometric redshifts at i < 22.5 AB and at 25 < i < 27 of less than 5 per-cent. Encouraged by this result, we present measurements of the deepest wide-field NIR-selected galaxy number counts and discuss several immediate science projects enabled by this work including the galaxy stellar mass and UV luminosity functions as well as constraints on the halo occupation distribution.

John R. Weaver
John R. Weaver
PhD Fellow in Astrophysics

My research interests lie almost exclusively within the realm of extragalactic astrophysics and cosmology. I use state-of-the-art optical and infrared observatories and surveys to study the lives of galaxies, and how their properties change over cosmic time. This includes detailed case studies of individual galaxies, as well as statistical analyses of large survey catalogs.