TY - JOUR
T1 - ACACIAS I
T2 - element abundance labels for 192 stars in the dwarf galaxy NGC 6822
AU - Ness, Melissa K.
AU - Mendel, J. Trevor
AU - Buder, Sven
AU - Wheeler, Adam
AU - Ji, Alexander P.
AU - Mijnarends, Luka
AU - Venn, Kim
AU - Starkenburg, Else
AU - Leaman, Ryan
AU - Grasha, Kathryn
AU - Aquilina, Sarah
N1 - Publisher Copyright:
© 2025 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society.
PY - 2025/3/1
Y1 - 2025/3/1
N2 - The element abundances of local group galaxies connect enrichment mechanisms to galactic properties and serve to contextualize 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 programme that leverages R=1800, SNR =15, IFU resolved spectra from the multi unit spectroscopic explorer . 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 ≈ 19 000 Milky Way LAMOST spectra with APOGEE labels. We report six inferred abundance labels (denoted lX), for 192 NGC 6822 disc stars, precise to ≈0.15 dex. We validate our generated spectral models provide a good fit to the data, including at individual atomic line features. We infer mean abundances of l[Fe/H] = -0.90 ± 0.03, l[Mg/Fe] = -0.01 ± 0.01, l [Mn/Fe] = -0.22 ± 0.02, l [Al/Fe] = -0.33 ± 0.03, l [C/Fe] =-0.43 ± 0.03, l [N/Fe] =0.18 ± 0.03. These abundance labels are similar to those of 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 extragalactic archaeology of characterizing the local group enrichment diversity using low-resolution, low signal to noise ratio IFU resolved spectra. Furthermore, we conclude that it is feasible to build a model based on spectra observed with one instrument and apply it to spectra obtained with another.
AB - The element abundances of local group galaxies connect enrichment mechanisms to galactic properties and serve to contextualize 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 programme that leverages R=1800, SNR =15, IFU resolved spectra from the multi unit spectroscopic explorer . 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 ≈ 19 000 Milky Way LAMOST spectra with APOGEE labels. We report six inferred abundance labels (denoted lX), for 192 NGC 6822 disc stars, precise to ≈0.15 dex. We validate our generated spectral models provide a good fit to the data, including at individual atomic line features. We infer mean abundances of l[Fe/H] = -0.90 ± 0.03, l[Mg/Fe] = -0.01 ± 0.01, l [Mn/Fe] = -0.22 ± 0.02, l [Al/Fe] = -0.33 ± 0.03, l [C/Fe] =-0.43 ± 0.03, l [N/Fe] =0.18 ± 0.03. These abundance labels are similar to those of 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 extragalactic archaeology of characterizing the local group enrichment diversity using low-resolution, low signal to noise ratio IFU resolved spectra. Furthermore, we conclude that it is feasible to build a model based on spectra observed with one instrument and apply it to spectra obtained with another.
KW - galaxies: abundances
KW - galaxies: individual: NGC 6822
KW - stars: abundances
KW - techniques: spectroscopic
UR - http://www.scopus.com/inward/record.url?scp=86000524809&partnerID=8YFLogxK
U2 - 10.1093/mnras/staf127
DO - 10.1093/mnras/staf127
M3 - Article
AN - SCOPUS:86000524809
SN - 0035-8711
VL - 537
SP - 2798
EP - 2818
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
IS - 3
ER -