Kavli Affiliate: Risa Wechsler
| First 5 Authors: Mithi A. C. de los Reyes, Yasmeen Asali, Risa Wechsler, Marla Geha, Yao-Yuan Mao
| Summary:
The stellar masses of galaxies are measured using integrated light via
several methods — however, few of these methods were designed for low-mass
($M_{star}lesssim10^{8}rm{M_{odot}}$) "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,
UniverseMachine-SAGA) and cosmological baryonic zoom-in simulations (MARVELous
Dwarfs and FIRE-2), to test literature color-$M_star/L$ relations and
multi-wavelength spectral energy distribution (SED) mass estimators. We
identify a list of "best practices" for measuring stellar masses of low-mass
galaxies from integrated photometry. These include updated prescriptions for
stellar mass based on $g-r$ color and WISE 3.4 $mu$m luminosity, which are
less systematically biased than literature calibrations and can recover true
stellar masses of low-mass galaxies with $sim0.1$ dex precision. When using
SED fitting to estimate stellar mass, we find that the form of the assumed star
formation history can induce significant biases: parametric SFHs can
underestimate stellar mass by as much as $sim0.4$ dex, while non-parametric
SFHs recover true stellar masses with insignificant offset ($-0.03pm0.11$
dex). However, we also caution that non-informative dust attenuation priors may
introduce $M_star$ uncertainties of up to $sim0.6$ dex.
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