The abundances of O, N, S, Cl, Ne, Ar, and Fe in H II regions of the Magellanic Clouds

TL;DR

This study uses deep spectroscopic data to analyze the physical conditions and chemical abundances in H II regions of the Magellanic Clouds, providing detailed insights into their composition and dust depletion factors.

Contribution

It presents the largest high-quality spectral dataset for Magellanic Cloud H II regions, enabling more accurate chemical abundance and dust depletion analysis than previous studies.

Findings

Fe depletion on dust grains similar to Galactic H II regions

Accurate chemical abundances for multiple elements in Magellanic Clouds

Constraints on abundance variations across each galaxy

Abstract

We use very deep spectra obtained with the Ultraviolet-Visual Echelle Spectrograph in the Very Large Telescope in order to determine the physical conditions, the chemical abundances and the iron depletion factors of four H II regions of the Large Magellanic Cloud and four H II regions of the Small Magellanic Cloud. The spectral range covered is 3100-10400 $\mathring{A}$ with a resolution of $\Delta\lambda \sim \lambda / 8800$. We measure the intensity of up to 200 emission lines in each object. Electron temperature and electron density are determined using different line intensity ratios. The ionic and total abundances are derived using collisionally excited lines for O, N, S, Cl, Ne, Ar, and Fe. The uncertainties are calculated using Monte Carlo simulations. This is the largest available set of high quality spectra for H II regions in the Magellanic Clouds. Thus, we can derive chemical abundances and depletion factors and constrain their variations across each galaxy with better accuracy than previous studies. In particular, we find that the amount of Fe depleted on to dust grains in the H II regions of the Magellanic Clouds is similar to that found in Galactic H II regions.