A homogeneous comparison between the chemical composition of the Large Magellanic Cloud and the Sagittarius dwarf galaxy

TL;DR

This study conducts a homogeneous high-resolution spectroscopic comparison of the chemical compositions of the Large Magellanic Cloud and Sagittarius dwarf galaxy, revealing similar enrichment histories but differences in heavy s-process elements and massive star contributions.

Contribution

It provides a consistent chemical abundance analysis of LMC and Sgr stars, reducing systematic biases and clarifying their true similarities and differences.

Findings

LMC and Sgr have similar abundance ratios for most elements.

Differences observed in heavy s-process elements Ba, La, Nd.

Galaxies show less contribution from massive stars compared to the Milky Way.

Abstract

Similarities in the chemical composition of two of the closest Milky Way satellites, namely the Large Magellanic Cloud (LMC) and the Sagittarius (Sgr) dwarf galaxy, have been proposed in the literature, suggesting similar chemical enrichment histories between the two galaxies. This proposition, however, rests on different abundance analyses, which likely introduce various systematics that hamper a fair comparison among the different data sets. In order to bypass this issue (and highlight real similarities and differences between their abundance patterns), we present a homogeneous chemical analysis of 30 giant stars in LMC, 14 giant stars in Sgr and 14 giants in the Milky Way, based on high-resolution spectra taken with the spectrograph UVES-FLAMES. The LMC and Sgr stars, in the considered metallicity range ([Fe/H]>-1.1 dex), show very similar abundance ratios for almost all the elements, with differences only in the heavy s-process elements Ba, La and Nd, suggesting a different contribution by asymptotic giant branch stars. On the other hand, the two galaxies have chemical patterns clearly different from those measured in the Galactic stars, especially for the elements produced by massive stars. This finding suggests the massive stars contributed less to the chemical enrichment of these galaxies with respect to the Milky Way. The derived abundances support similar chemical enrichment histories for the LMC and Sgr.