Strategies for Obtaining Robust Spectral Energy Distribution Fitting Parameters for Galaxies at z ∼ 1 and z ∼ 2 in the Absence of Infrared Data

Abstract

Robust estimation of star formation rates (SFRs) at higher redshifts (z ≳ 1) using UV–optical–near-infrared (NIR) photometry is contingent on the ability of spectral energy distribution (SED) fitting to constrain the dust attenuation, stellar metallicity, and star formation history (SFH) simultaneously. IR-derived dust luminosities can help break the degeneracy between these parameters, but IR data are often not available. Here, we explore strategies for SED fitting at z ≳ 1 in the absence of IR data using a sample of log M * > 10.2 star-forming galaxies from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) for which 24 μm data are available. We adopt the total IR luminosity (L TIR) obtained from 24 μm as the “ground truth,” which allows us to assess how well it can be recovered (as L dust) from UV–optical–NIR SED fitting. We test a variety of dust attenuation models, stellar population synthesis models, metallicity assumptions, and SFHs separately to identify which assumptions maximize the agreement (correlation and linearity) between L TIR and L dust. We find that a flexible dust attenuation law performs best. For stellar populations, we find that Bruzual & Charlot models are favored over those of Eldridge et al. Fixing the stellar metallicity at solar value is preferred to other fixed values or leaving it as a free parameter. For SFHs, we find that minimizing the variability in the recent (<100 Myr) SFH improves the agreement with L TIR. Finally, we provide a catalog of galaxy parameters (including M * and SFR) for CANDELS galaxies with logM*>8 and 0.7 < z < 1.3, obtained using the models we found to be the most robust.