The Impact of Star Formation Histories on Stellar Mass Estimation: Implications from the Local Group Dwarf Galaxies [GA]

Local Group (LG) galaxies have relatively accurate SFHs and metallicity evolution derived from resolved CMD modeling, and thus offer a unique opportunity to explore the efficacy of estimating stellar mass M${\star}$ of real galaxies based on integrated stellar luminosities. Building on the SFHs and metallicity evolution of 40 LG dwarf galaxies, we carried out a comprehensive study of the influence of SFHs, metallicity evolution and dust extinction on the UV-to-NIR color-$\mathcal{M/L}$ (color-log$\Upsilon{\star}$($\lambda$)) relations and M${\star}$ estimation of local universe galaxies. We find that: The LG galaxies follow color-log$\Upsilon{\star}$($\lambda$) relations that fall in between the ones calibrated by previous studies; Optical color-log$\Upsilon_{\star}$($\lambda$) relations at higher metallicities ([M/H]) are generally broader and steeper; The SFH “concentration” does not significantly affect the color-log$\Upsilon_{\star}$($\lambda$) relations; Light-weighted ages and [M/H] together constrain log$\Upsilon_{\star}$($\lambda$) with uncertainties ranging from $\lesssim$ 0.1 dex for the NIR up to 0.2 dex for the optical passbands; Metallicity evolution induces significant uncertainties to the optical but not NIR $\Upsilon_{\star}$($\lambda$) at given light-weighted ages and [M/H]; The $V$ band is the ideal luminance passband for estimating $\Upsilon_{\star}$($\lambda$) from single colors, because the combinations of $\Upsilon_{\star}$($V$) and optical colors such as $B-V$ and $g-r$ exhibit the weakest systematic dependence on SFHs, [M/H] and dust extinction; Without any prior assumption on SFHs, M${\star}$ is constrained with biases $\lesssim$ 0.3 dex by the optical-to-NIR SED fitting. Optical passbands alone constrain M${\star}$ with biases $\lesssim$ 0.4 dex (or $\lesssim$ 0.6 dex) when dust extinction is fixed (or variable) in SED fitting. [abridged]

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H. Zhang, T. Puzia and D. Weisz
Fri, 13 Oct 17

Comments: 35 pages, 31 figures, 2 tables, accepted by ApJS