The dust attenuation scaling relation of star-forming galaxies in the eagle simulations

Abstract

ABSTRACT Dust attenuation in star-forming galaxies (SFGs), as parametrized by the infrared excess (IRX ≡ LIR/LUV), is found to be tightly correlated with star formation rate, metallicity, and galaxy size, following a universal IRX relation up to z = 3. This scaling relation can provide a fundamental constraint for theoretical models to reconcile galaxy star formation, chemical enrichment, and structural evolution across cosmic time. We attempt to reproduce the universal IRX relation over 0.1 ≤ z ≤ 2.5 using the Evolution and Assembly of GaLaxies and their Environments (EAGLE) hydrodynamical simulations and examine sensitive parameters in determining galaxy dust attenuation. Our findings show that while the predicted universal IRX relation from EAGLE approximately aligns with observations at z ≤ 0.5, noticeable disparities arise at different stellar masses and higher redshifts. Specifically, we investigate how modifying various galaxy parameters can affect the predicted universal IRX relation in comparison to the observed data. We demonstrate that the simulated gas-phase metallicity is the critical quantity for the shape of the predicted universal IRX relation. We find that the influence of the infrared luminosity and infrared excess is less important while galaxy size has virtually no significant effect. Overall, the EAGLE simulations are not able to replicate some of the observed characteristics between IRX and galaxy parameters of SFGs, emphasizing the need for further investigation and testing for our current state-of-the-art theoretical models.