Accuracy of Stellar Mass-to-light Ratios of Nearby Galaxies in the Near-Infrared

TL;DR

This study assesses the accuracy of stellar mass-to-light ratios in nearby galaxies using near-infrared spectral data, highlighting the optimal wavelength for mass estimation and the importance of star formation rate corrections.

Contribution

It provides a detailed analysis of $M_*/L$ ratios across 0.75-5.0 μm, identifying the wavelength with minimal scatter and demonstrating improved mass estimates when accounting for star formation rates.

Findings

Minimum $M_*/L$ scatter (~0.10 dex) at 1.6 μm.

Correcting for SFR dependence reduces scatter to 0.02 dex.

Stellar mass can be estimated with ~0.02 dex accuracy using infrared spectra and SFR prior.

Abstract

Future satellite missions are expected to perform all-sky surveys, thus providing the entire sky near-infrared spectral data and consequently opening a new window to investigate the evolution of galaxies. Specifically, the infrared spectral data facilitate the precise estimation of stellar masses of numerous low-redshift galaxies. We utilize the synthetic spectral energy distribution (SED) of 2853 nearby galaxies drawn from the DustPedia (435) and Stripe 82 regions (2418). The stellar mass-to-light ratio ($M_*/L$) estimation accuracy over a wavelength range of $0.75-5.0$ $\mu$m is computed through the SED fitting of the multi-wavelength photometric dataset, which has not yet been intensively explored in previous studies. We find that the scatter in $M_*/L$ is significantly larger in the shorter and longer wavelength regimes due to the effect of the young stellar population and the dust contribution, respectively. While the scatter in $M_*/L$ approaches its minimum ($\sim0.10$ dex) at $\sim1.6$ $\mu$m, it remains sensitive to the adopted star formation history model. Furthermore, $M_*/L$ demonstrates weak and strong correlations with the stellar mass and the specific star formation rate (SFR), respectively. Upon adequately correcting the dependence of $M_*/L$ on the specific SFR, the scatter in the $M_*/L$ further reduces to $0.02$ dex at $\sim1.6$ $\mu$m. This indicates that the stellar mass can be estimated with an accuracy of $\sim0.02$ dex with a prior knowledge of SFR, which can be estimated using the infrared spectra obtained with future survey missions.