Authors
Abstract
The stellar masses of galaxies are measured from integrated light via several methods—however, few of these methods were designed for low-mass (M⋆ ≲ 108 M⊙) "dwarf" galaxies, whose properties (e.g., stochastic star formation, low metallicity) pose unique challenges for estimating stellar masses. In this work, we quantify the precision and accuracy at which stellar masses of low-mass galaxies can be recovered using UV/optical/IR photometry. We use mock observations of 469 low-mass galaxies from a variety of models, including both semi-empirical models (GRUMPY and UniverseMachine-SAGA) and cosmological baryonic zoom-in simulations (MARVELous Dwarfs and FIRE-2), to test literature color–M⋆/L relations and multiwavelength spectral energy distribution (SED) mass estimators. We identify a list of "best practices" for measuring stellar masses of low-mass galaxies from integrated photometry. We find that literature color–M⋆/L relations are often unable to capture the bursty star formation histories (SFHs) of low-mass galaxies, and we develop an updated prescription for stellar mass based on g ‑ r color that is better able to recover stellar masses for the bursty low-mass galaxies in our sample (with ∼0.1 dex precision). SED fitting can also precisely recover stellar masses of low-mass galaxies, but this requires thoughtful choices about the form of the assumed SFH: Parametric SFHs can underestimate stellar mass by as much as ∼0.4 dex, while nonparametric SFHs recover true stellar masses with insignificant offset (‑0.03 ± 0.11 dex). Finally, we also caution that noninformative (wide) dust attenuation priors may introduce M⋆ uncertainties of up to ∼0.6 dex.Details
| Publication | The Astrophysical Journal, Volume 989, Issue 1, id.91, 23 pp. |
| Publication Date | August 2025 |
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| arXiv | arXiv:2409.03959 |
| Bibcode | 2025ApJ...989...91D |
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| E-Print Comment(s) | 29 pages including references, 11 figures; accepted to ApJ |