Spatial disconnection between stellar and dust emissions: the test of the Antennae Galaxies (Arp 244)

TL;DR

This study tests the validity of energy balance spectral energy distribution modeling on the Antennae Galaxies, revealing consistent star formation and dust properties despite spatial disconnection between ultraviolet and infrared emissions.

Contribution

It demonstrates that energy balance models can reliably infer galaxy properties even with spatially disconnected stellar and dust emissions, using high-resolution data from the Antennae Galaxies.

Findings

Consistent estimates of star formation rate, stellar mass, and dust attenuation from regional and whole-galaxy analysis.

Spatially resolved attenuation curves show flattening with increased dust density, aligning with simulation predictions.

The spatial disconnection does not significantly bias the physical parameter estimates from SED fitting.

Abstract

The detection with of the Atacama Large Millimeter Array (ALMA) of dust-rich high redshift galaxies whose cold dust emission is spatially disconnected from the ultraviolet emission bears a challenge for modelling their spectral energy distributions (SED) with codes based on an energy budget between the stellar and dust components. We test the validity of energy balance modelling on a nearby resolved galaxy with vastly different ultraviolet and infrared spatial distributions and infer what information can be reliably retrieved from the analysis of the full spectral energy distribution. We use 15 broadband images of the Antennae Galaxies ranging from far-ultraviolet to far-infrared and divide Arp 244 into 58 square ~1 kpc$^2$ regions. We fit the data with CIGALE to determine the star formation rate, stellar mass and dust attenuation of each region. We compare these quantities for the addition of the 58 regions to the ones obtained for Arp 244 as a whole and find that both estimates are consistent within one sigma. We present the spatial distribution of these physical parameters as well as the shape of the attenuation curve across the Antennae Galaxies . We also observe a flattening of the attenuation curves with increasing attenuation and dust surface density in agreement with the predictions of hydrodynamical simulations coupled with radiative transfer modelling.