Mock Lightcones and Theory Friendly Catalogs for the CANDELS Survey

TL;DR

This paper introduces mock galaxy catalogs for the CANDELS survey, created from simulations and models, to aid in interpreting observations and exploring field-to-field variance.

Contribution

It provides the first set of mock lightcones tailored for CANDELS, combining multiple galaxy formation models and making them publicly available.

Findings

Good agreement with observed luminosity and stellar mass functions.

Poorer agreement for galaxy colors and star formation rates.

Multiple realizations enable variance analysis.

Abstract

We present mock catalogs created to support the interpretation of the CANDELS survey. We extract halos along past lightcones from the Bolshoi Planck dissipationless N-body simulations and populate these halos with galaxies using two different independently developed semi-analytic models of galaxy formation and the empirical model UniverseMachine. Our mock catalogs have geometries that encompass the footprints of observations associated with the five CANDELS fields. In order to allow field-to-field variance to be explored, we have created eight realizations of each field. In this paper, we present comparisons with observable global galaxy properties, including counts in observed frame bands, luminosity functions, color-magnitude distributions and color-color distributions. We additionally present comparisons with physical galaxy parameters derived from SED fitting for the CANDELS observations, such as stellar masses and star formation rates. We find relatively good agreement between the model predictions and CANDELS observations for luminosity and stellar mass functions. We find poorer agreement for colors and star formation rate distributions. All of the mock lightcones as well as curated "theory friendly" versions of the observational CANDELS catalogs are made available through a web-based data hub.