Multiple channels for nitrogen pollution by metal enriched supermassive stars and implications for GN-z11

Abstract

GN-z11 is an unusually luminous high redshift galaxy which was recently observed to have strong nitrogen lines while at the same time lacking traditional signatures of AGN activity. These observations have been interpreted as a super-solar nitrogen abundance which is challenging to explain with standard stellar evolution and supernovae enrichment. We present simulations of four models of metal enriched supermassive stars after the zero age main sequence which produce super-solar nitrogen consistent with the observations of GN-z11. We then show that the most massive model ends its life in a violent explosion which results in even greater nitrogen pollution.