Events at Physics |
The measured chemical abundances in galaxies are useful for constraining their formation histories and the details of their evolution. The abundance of oxygen has been shown to trace the buildup of stellar mass in galaxies on both global and local scales. Nitrogen, however, is produced on different timescales to oxygen, and therefore may provide a secondary constraint on our galaxy evolution models. I use data from the SDSS IV: Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) survey to investigate whether similar scaling relations hold for nitrogen as for oxygen. I find that the observed abundances cannot be explained by simple models for the evolution of nitrogen in galaxies. Contrary to previous literature, the ratio of N/O depends on the, star formation rate, total stellar mass and sizes of galaxies. These results pose problems for the universal applicability of some optical gas-phase metallicity calibrations. They also hint that our understanding of how nitrogen is produced and dispersed within galaxies may require revision.