Decoding the IRX–β dust attenuation relation in star-forming galaxies at intermediate redshift

Abstract

Aims. We aim to understand what drives the IRX–β dust attenuation relation at intermediate redshifts (0.5 < z < 0.8) in star-forming galaxies. We investigate the role of various galaxy properties in shaping this observed relation. Methods. We used robust [O II]λ3727, [O III]λλ4959,5007, and Hβ line detections of our statistical sample of 1049 galaxies to estimate the gas-phase metallicities. We derived key physical properties that are necessary to study galaxy evolution, such as the stellar masses and the star formation rates, using the spectral energy distribution fitting tool CIGALE. Equivalently, we studied the effect of galaxy morphology (mainly the Sérsic index n and galaxy inclination) on the observed IRX–β scatter. We also investigated the role of the environment in shaping dust attenuation in our sample. Results. We find a strong correlation with respect to the IRX–β relation on the gas-phase metallicity in our sample, as well as a strong correlation with galaxy compactness characterized by the Sérsic indexes. With higher metallicities, galaxies move along the track of the IRX–β relation towards higher IRX. Correlations are also seen with the stellar masses, specific star formation rates, and the stellar ages of our sources. Metallicity is strongly correlated with the IRX–β scatter, which also results from the presence of older stars and higher masses at higher beta values. Galaxies with higher metallicities show higher IRX and beta values. The correlation with specific dust mass strongly shifts the galaxies away from the IRX–β relation towards lower β values. We find that more compact galaxies go through a greater amount of attenuation than less compact galaxies. There is a subtle variation in the dust attenuation scatter between edge-on and face-on galaxies, but the difference is not statistically significant. Galaxy environments do not significantly affect dust attenuation in our sample of star-forming galaxies at intermediate redshift.