A Spectral Atlas for Quiescent Galaxies

TL;DR

This paper compiles a spectral feature atlas for quiescent galaxies, aiding interpretation of their stellar populations and gas properties using JWST data in the optical to near-infrared range.

Contribution

It provides a comprehensive reference table of spectral features with diagnostic information, enhancing analysis of galaxy spectra in the JWST era.

Findings

Key spectral features and their physical origins identified

Diagnostic table indicating sensitivity to age, metallicity, and other parameters

Facilitates interpretation of JWST spectra of quiescent galaxies

Abstract

Key absorption features in the spectra of massive quiescent galaxies reveal a wealth of information about their stellar populations and, in some cases, the properties of gas within and around them. With the spectroscopic capabilities of \textit{JWST}, we are now able to probe deeper and farther into the near-infrared than ever before. It is therefore crucial that we fully understand the origins of observed spectral absorption and emission features. The goal of this document is to collate important rest-frame optical to near-infrared (NIR) spectral features of quiescent galaxies in the context of their physical origin (e.g., stellar photospheres, the interstellar medium, or a combination thereof). We present a look-up table summarizing key information, including a ``diagnostic'' column indicating whether lines are most sensitive to age, metallicity, surface gravity (IMF sensitivity), $\alpha$-enhancement, electron temperature or gas density. This compilation is intended to serve as a practical reference for interpreting rest-optical-NIR spectral features in quiescent galaxies, particularly as \textit{JWST} spectroscopy enables increasingly detailed studies of their stellar populations and surrounding gas.