Kavli Affiliate: Alexander P. Ji
| First 5 Authors: Melissa K. Ness, J. Trevor Mendel, Sven Buder, Adam Wheeler, Alexander P. Ji
| Summary:
The element abundances of local group galaxies connect enrichment mechanisms
to galactic properties and serve to contextualise the Milky Way’s abundance
distributions. Individual stellar spectra in nearby galaxies can be extracted
from Integral Field Unit (IFU) data, and provide a means to take an abundance
census of the local group. We introduce a program that leverages $R=1800$,
$mathrm{SNR}=15$, IFU resolved spectra from the Multi Unit Spectroscopic
Explorer (MUSE). We deploy the data-driven modelling approach for labelling
stellar spectra with stellar parameters and abundances, of The Cannon, on
resolved stars in NGC 6822. We construct our model for The Cannon using
$approx$19,000 Milky Way LAMOST spectra with APOGEE labels. We report six
inferred abundance labels (denoted $ell_mathrm{X}$), for 192 NGC 6822 disk
stars, precise to $approx$$0.15$ dex. We validate our generated spectral
models provide a good fit the data, including at individual atomic line
features. We infer mean abundances of $ell_mathrm{[Fe/H]} = -0.90 pm 0.03$,
$ell_mathrm{[Mg/Fe]} = -0.01 pm 0.01$, $ell_mathrm{[Mn/Fe]} = -0.22 pm
0.02$, $ell_mathrm{[Al/Fe]} = -0.33 pm 0.03$, $ell_mathrm{[C/Fe]} =-0.43
pm 0.03$, $ell_mathrm{[N/Fe]} =0.18 pm 0.03$. These abundance labels are
similar to dwarf galaxies observed by APOGEE, and the lower enhancements for
NGC 6822 compared to the Milky Way are consistent with expectations. This
approach supports a new era in extra-galactic archaeology of characterising the
local group enrichment diversity using low-resolution, low-SNR IFU resolved
spectra.
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