Context. SDSS-IV APOGEE-2, GALAH, and Gaia-ESO are high-resolution, ground-based, multi-object spectroscopic surveys providing fundamental stellar atmospheric parameters and multiple elemental abundance ratios for hundreds of thousands of stars of the Milky Way. Data from these and other surveys contribute to investigations of the history and evolution of the Galaxy.
Aims: We undertake a comparison between the most recent data releases of these surveys to investigate the accuracy and precision of derived parameters by placing the abundances on an absolute scale. We also discuss the correlations in parameter and abundance differences as a function of main parameters. Uncovering the variants provides a basis to continue the efforts of future sky surveys.
Methods: Quality samples from the APOGEE−GALAH (15 537 stars), APOGEE−GES (804 stars), and GALAH−GES (441 stars) overlapping catalogs were collected. We investigated the mean variants between the surveys, and linear trends were also investigated. We compared the slope of correlations and mean differences with the reported uncertainties.
Results: The average and scatter of vrad, Teff, log g, [M/H], and vmicro, along with numerous species of elemental abundances in the combined catalogs, show that in general there is a good agreement between the surveys. We find large radial velocity scatters ranging from 1.3 km s−1 to 4.4 km s−1 when comparing the three surveys. We observe some weak trends (e.g., in ΔTeff vs. Δlog g for the APOGEE−GES stars) and a clear correlation in the vmicro − Δvmicro planes in the APOGEE−GALAH common sample. For [α/H], [Ti/H] (APOGEE−GALAH giants), and [Al/H] (APOGEE−GALAH dwarfs) potential strong correlations are discovered as a function of the differences in the main atmospheric parameters, and we also find weak trends for other elements.
Conclusions: In general we find good agreement between the three surveys within their respective uncertainties. However, there are certain regimes in which strong variants exist, which we discuss. There are still offsets larger than 0.1 dex in the absolute abundance scales.