Estimating Dust Attenuation from Galactic Spectra. III. Radial Variations of Dust Attenuation Scaling Relations in MaNGA Galaxies

Abstract We investigate the radial dependence of the scaling relations of dust attenuation in nearby galaxies using integral field spectroscopy data from MaNGA. We identify ionized gas regions of kiloparsec size from MaNGA galaxies, and for each region we estimate both the stellar attenuation E ( B − V ) star and gas attenuation E ( B − V ) gas . We then quantify the correlations of 15 regional/global properties with E ( B − V ) gas and E ( B − V ) star , using both the feature importance obtained with the Random Forest regression technique and the Spearman correlation coefficients. The importance of stellar mass, metallicity, and nebular velocity dispersion found previously from studies based on the Sloan Digital Sky Survey can be reproduced if our analysis is limited to the central region of galaxies. The scaling relations of both E ( B − V ) gas and E ( B − V ) star are found to vary strongly as one goes from the galactic center to outer regions, and from H α -bright regions to H α -faint regions. For E ( B − V ) gas , [N ii ]/[S ii ] is top-ranked with a much higher correlation coefficient than any other property at 0 < R ≲ R e , while [O iii ]/[O ii ] outperforms [N ii ]/[S ii ] as the leading property in the outermost region. For E ( B − V ) star , stellar age shows the strongest correlation with no/weak dependence on radial distance, although Σ H α and specific star formation rate present similarly strong correlations with E ( B − V ) star in the galactic center. We find H α -bright regions to generally show stronger correlations with E ( B − V ) gas , while H α -faint regions are more strongly correlated with E ( B − V ) star , although this depends on individual properties and radial distance. The implications of our results for studies of high- z galaxies are discussed.