SDSS+JWST Census of Stellar and Nebular Dust Attenuation at $z\sim 0$-7: Mass Dependence and Redshift Evolution

Abstract

We present the demography of dust attenuation, including its mass dependence and redshift evolution, using spectroscopic samples of 34,182 SDSS galaxies at $z\sim 0.1$ and 863 JWST/JADES galaxies at $z\sim 1.5$--$7$. We find that, on average, $\mathrm{H}\alpha /\mathrm{H}\beta$ ratios are comparable to the Case B recombination value at $M_{\ast }\lesssim 10^9{M}_{\odot }$, and increase beyond $M_{\ast }\sim 10^9{M}_{\odot }$ both at $z\sim 0.1$ and $1.5$--$7$. We derive the nebular attenuation $A_{\mathrm{V},\mathrm{nebular}}$ from Balmer decrements and the stellar attenuation $A_{\mathrm{V},\mathrm{stellar}}$ from rest-frame UV--optical spectra with supplementary \textit{GALEX} data, via comparisons with stellar-population models and multiple attenuation curves in a consistent manner across cosmic time. We find no significant redshift evolution of $A_{\mathrm{V},\mathrm{nebular}}$ and $A_{\mathrm{V},\mathrm{stellar}}$ at fixed $M_{\ast }$ over $z\sim 0$--$7$, forming a universal extinction relation, and both rise from $0.2$--$0.4$ at $M_{\ast }\lesssim 10^9{M}_{\odot }$ to $\sim 1$ at $M_{\ast }\sim 10^{11}{M}_{\odot }$. Interestingly, at $M_{\ast }\gtrsim 10^9{M}_{\odot }$, $A_{\mathrm{V},\mathrm{nebular}}$ rises more steeply than $A_{\mathrm{V},\mathrm{stellar}}$. This correlation holds within an uncertainty of $\sim \pm 0.2$ for various combinations of attenuation curves (Calzetti, SMC, and Milky Way). These results indicate that $M_{\ast }\sim 10^9{M}_{\odot }$ is a transition mass in dust attenuation, whose low-mass behavior reflects dust widely distributed by feedbacks. These mass-dependent extinction results address the long-standing issue of appropriate choice of the stellar-to-nebular color excess ratio, $f\equiv E(B-V{)}_{\mathrm{stellar}}/E(B-V{)}_{\mathrm{nebular}}=1.0$ or $0.44$, and suggest that galaxy $M_{\ast }$ determines $f$ from $\sim 1.0$ to $\sim 0.44$ across low- to high-mass galaxies.

25 pages, 13 figures, submitted to ApJ, comments are welcome