# The Imprint of Element Abundance Patterns on Quiescent Galaxy SEDs

## TL;DR

This study demonstrates that detailed elemental abundance patterns significantly influence the spectral energy distributions of quiescent galaxies, and incorporating these variations into models enables accurate reproduction of observed broadband colors.

## Contribution

It introduces a novel approach combining full-spectrum fitting with updated stellar spectral libraries to accurately predict galaxy SEDs based on elemental abundances.

## Key findings

- SEDs can be predicted within 0.03 mag accuracy using this method.
- Full optical to NIR SEDs require models that capture absorption line behavior.
- Ignoring abundance patterns can bias broadband photometry modeling.

## Abstract

Stellar population synthesis (SPS) models have long struggled to reproduce observed optical through near-IR (NIR) spectral energy distributions (SED) of massive quiescent galaxies. We revisit this issue using a novel approach that combines the diagnostic power of full-spectrum fitting with recently updated stellar spectral libraries. First, we perform full-spectrum fitting of continuum-normalized stacked SDSS spectra in bins of velocity dispersion to infer their stellar population properties, such as the elemental abundances and age. Next, we use the resulting best-fit parameters to compute $ugriz$ colors, which are then compared to observed colors of the same galaxies. With this approach we are able to predict the $ugriz$ SEDs of low and high mass galaxies at the $\lesssim 0.03$ mag level in nearly all cases. We find that the full optical through NIR SEDs of quiescent galaxies can be reproduced only when the spectrum is fit with a flexibility that is able to capture the behavior of the entire optical absorption line spectrum. The models include variations in individual elemental abundances, nebular emission lines, and the presence of young stellar components. The successful prediction of the SED shape from continuum-normalized spectra implies that the continuum information is largely contained in the narrow absorption features. These results also imply that attempts to model broadband photometry of quiescent systems will suffer from potentially significant biases if the detailed abundance patterns are not taken into account.