Speaker
Description
The heavy element abundance profiles of galaxies place stringent constraints on galaxy growth and assembly history. Low-redshift galaxies generally have a negative metallicity gradient in their gas and stars. Such gradients are thought to be a natural manifestation of galaxy inside-out formation. As the Milky Way is currently the only spiral galaxy in which we can measure temporally-resolved chemical abundances, it enables unique insights into the origin of metallicity gradients and their correlation with the growth history of galaxies. However, until now, these abundance profiles have not been translated into the integrated-light measurements that are needed to compare the Milky Way with the general galaxy population. In this talk I will introduce our recent work in which we report this measurement of the light-weighted, integrated stellar metallicity profile of our Galaxy using APOGEE data. We find that the integrated stellar metallicity profile of the Milky Way has a ‘∧’-like broken shape, with a mildly positive gradient inside a Galactocentric radius of 7 kpc and a steep negative gradient outside. This broken integrated metallicity profile of the Milky Way is not unique but is not common among Milky Way-mass star-forming galaxies observed in the MaNGA survey and simulated in the TNG50 cosmological simulation. Our results suggest the Milky Way might not have a typical metallicity distribution for a galaxy of its mass, and thus offers valuable insight into the rich variety of galaxy enrichment processes.
