The TNG50-SKIRT Atlas: Multi-wavelength nonparametric galaxy morphology

TL;DR

This study uses the TNG50-SKIRT Atlas to analyze how galaxy morphology indicators vary with wavelength and dust, revealing significant wavelength dependence especially in disc galaxies, consistent with observational data.

Contribution

It provides a comprehensive analysis of wavelength and dust effects on nonparametric galaxy morphology using simulated data, aligning with real observations.

Findings

Morphology indicators vary significantly with wavelength.

Wavelength dependence is stronger in disc-dominated galaxies.

Dust attenuation has a modest overall effect but can be significant for individual galaxies.

Abstract

Context: Galaxy morphology is a fundamental property to describe galaxy evolution. However, the observed morphology of a particular galaxy may depend on the observed wavelength. Aims: Our aim is to investigate the wavelength dependence and the effect of dust attenuation on nonparametric morphology indicators. Methods: We use the TNG50-SKIRT Atlas, an atlas of synthetic UV to near-infrared (NIR) broadband images for a complete stellar-mass-selected sample of 1154 galaxies extracted from the TNG50 cosmological simulation at $z = 0$. For each image, we calculate four nonparametric morphology indicators using the StatMorph code. Results: We find that the known correlations between the stellar mass and the morphological parameters measured in the optical, together with the Gini-$M_{20}$, concentration-Gini, and concentration-$M_{20}$ planes, are fully consistent with observational data. However, nonparametric morphological indicators change significantly with wavelength and that this wavelength dependence is stronger for disc-dominated than for bulge-dominated galaxies. The wavelength dependence of the morphology of our simulated TNG50 galaxies is consistent with measurements of local galaxies from the SINGS survey. We demonstrate that the effect of dust attenuation on nonparametric morphology indicators is modest across the full galaxy population but can be significant for individual galaxies.