The Interstellar Medium Scaling Relations Using Inner H i and an Application of Estimating Dust Mass

Abstract

We select a disk-like galaxy sample with observations of the H I, H2, and dust from the Herschel Reference Survey, and derive inner H I masses within the optical radius. We find that the inner gas-to-dust ratio is almost independent of gas-phase metallicity, and confirm that the inner gas mass (H I+H2) shows a tighter relation with dust mass and monochromatic 500 μm luminosity than the integral gas mass. It supports that dust is more closely associated with cospatial cold gas than the overall cold gas. Based on the newly calibrated relationship between inner gas mass and dust mass, we predict dust masses for disk-dominated galaxies from the xCOLD GASS sample. The predicted dust masses show scaling relations consistent with fiducial ones in the literature, supporting their robustness. Additionally, we find that at a given dust mass and star formation rate (SFR), the galactic Wide-field Infrared Explorer W3 luminosities show a significant dependence on the [N ii] luminosity and the stellar mass surface density. Such dependence highlights the caveat of using the W3 luminosity as an integral SFR indicator, and is consistent with findings of studies that target star-forming regions in more nearby galaxies and accurately derive dust masses based on mapping-mode spectroscopy.