Speaker
Description
Chemical cartography of the Galactic disk provides insights to its structure and assembly history over cosmic time. In this work, we use chemical cartography to explore chemical gradients and azimuthal substructure in the Milky Way disk with giant stars from APOGEE DR17. We confirm the existence of a radial metallicity gradient in the disk of ~ -0.0702 ± 0.0004 dex/kpc and a vertical metallicity gradient of ~ -0.164 ± 0.001. We find azimuthal variations (±0.1 dex) on top of the radial metallicity gradient that have been previously established with other surveys. The APOGEE giants show variations in their [Fe/H] gradient that spatially align with the position of the spiral arms. Beyond iron, we show, for the first time, that other elements (e.g., Mg, O) display azimuthal variations across the Galactic disk. The strength of the azimuthal variations appear to be age-dependent. This analysis, while completed with SDSS-IV, provides a blueprint for a future SDSS-V project.
