On the Simultaneous Modelling of Dust and Stellar Populations for Interpretation of Galaxy Properties

TL;DR

This study compares how different stellar population and dust emission models affect the interpretation of galaxy spectral energy distributions, revealing biases and the importance of model choices in understanding galaxy properties.

Contribution

It introduces a framework for assessing the impact of stellar and dust model choices on galaxy property derivations, highlighting the effects of binary evolution and dust components.

Findings

Including binary stellar evolution biases dust and stellar parameter estimates.

Dusty stellar birth cloud models improve fit flexibility and sensitivity.

Binary populations suggest longer birth cloud dissipation timescales.

Abstract

The physical properties of galaxies are encoded within their spectral energy distribution and require comparison with models to be extracted. These models must contain a synthetic stellar population and, where infrared data is to be used, also consider prescriptions for energy reprocessing and re-emission by dust. While many such models have been constructed, there are few analyses of the impact of stellar population model choice on derived dust parameters, or vice versa. Here we apply a simple framework to compare the impact of these choices, combining three commonly-used stellar population synthesis models and three dust emission models. We compare fits to the ultraviolet to far-infrared spectral energy distributions of a validation sample of infrared-luminous galaxies. We find that including different physics, such as binary stellar evolution, in the stellar synthesis model can introduce biases and uncertainties in the derived parameters of the dust and stellar emission models, largely due to differences in the far-ultraviolet emission available for reprocessing. This may help to reconcile the discrepancy between the cosmic star formation rate and stellar mass density histories. Notably the inclusion of a dusty stellar birth cloud component in the dust emission model provides more flexibility in accommodating the stellar population model, as its reemission is highly sensitive to the ultraviolet radiation field spectrum and density. Binary populations favour a longer birth cloud dissipation timescale than is found when assuming only single star population synthesis.