Nonparametric galaxy morphology from UV to submm wavelengths

TL;DR

This study applies nonparametric morphological analysis across UV to submm wavelengths for spiral galaxies, revealing dust distribution characteristics and providing a new test for cosmological simulations.

Contribution

It introduces the first multi-wavelength nonparametric morphological analysis of spiral galaxies, highlighting dust distribution differences and offering a novel observational benchmark.

Findings

Dust is more extended and clumpy than stars.

Morphological indicators vary significantly between dust and stellar maps.

Provides a new observational test for galaxy formation models.

Abstract

We present the first nonparametric morphological analysis of a set of spiral galaxies from UV to submm wavelengths. Our study is based on high-quality multi-wavelength imaging for nine well-resolved spiral galaxies from the DustPedia database, combined with nonparametric morphology indicators calculated in a consistent way using the {\tt{StatMorph}} package. We measure the half-light radius, the concentration index, the asymmetry index, the smoothness index, the Gini coefficient and the $M_{20}$ indicator in various wavebands from UV to submm wavelengths, as well as in stellar mass, dust mass and star formation rate maps. We find that the interstellar dust in galaxies is distributed in a more extended, less centrally concentrated, more asymmetric, and more clumpy way than the stars. This is particularly evident when comparing morphological indicators based on the stellar mass and dust mass maps. This should serve as a warning sign against treating the dust in galaxies as a simple smooth component. We argue that the nonparametric galaxy morphology of galaxies from UV to submm wavelengths is an interesting test for cosmological hydrodynamics simulations.