# The MUSE Atlas of Disks (MAD): Resolving Star Formation Rates and Gas Metallicities on < 100pc Scales

## TL;DR

This study uses high-resolution MUSE observations to analyze ionized gas properties, star formation rates, and metallicity gradients in 38 nearby disk galaxies at <100 pc scales, revealing local relations and inside-out growth patterns.

## Contribution

It provides the first detailed analysis of resolved gas metallicities and star formation rates on <100 pc scales, disentangling HII regions from diffuse gas and confirming local origins of key galactic relations.

## Key findings

- Metallicity decreases with radius in galaxy disks.
- HII regions have higher metallicity than diffuse ionized gas.
- Resolved mass-metallicity and star formation relations are local and independent of total stellar mass.

## Abstract

We study the physical properties of the ionized gas in local disks using the sample of 38 nearby $\sim10^{8.5-11.2}$M$_\odot$ Star-Forming Main Sequence (SFMS) galaxies observed so far as part of the MUSE Atlas of Disks (MAD). Specifically, we use all strong emission lines in the MUSE wavelength range 4650-9300 \AA\ to investigate the resolved ionized gas properties on $\sim$100 pc scales. This spatial resolution enables us to disentangle HII regions from the Diffuse Ionized Gas (DIG) in the computation of gas metallicities and Star Formation Rates (SFRs) of star forming regions. The gas metallicities generally decrease with radius. The metallicity of the HII regions is on average $\sim$0.1 dex higher than that of the DIG, but the metallicity radial gradient in both components is similar. The mean metallicities within the inner galaxy cores correlate with the total stellar mass of the galaxies. On our <100 pc scales, we find two correlations previously reported at kpc scales: a spatially resolved Mass-Metallicity Relation (RMZR) and a spatially resolved SFMS (RSFMS). We find no secondary dependency of the RMZR with the SFR density. We find that both resolved relations have a local origin, as they do not depend on the total stellar mass. The observational results of this paper are consistent with the inside-out scenario for the growth of galactic disks.