Stellar Population and Metal Production in AGN Disks

TL;DR

This paper explores the formation, evolution, and explosive nucleosynthetic yields of massive stars in AGN disks, proposing that these processes influence observed chemical signatures and black hole formation in active galactic nuclei.

Contribution

It introduces a novel study of massive star evolution and nucleosynthesis in AGN disks, highlighting their potential role in chemical enrichment and compact object formation.

Findings

Massive stars in AGN disks can eject significant iron during collapse.

Nucleosynthetic yields can constrain the number of such systems.

Rapid rotation influences the explosion and element ejection processes.

Abstract

As gravitational wave detections increase the number of observed compact binaries (consisting of neutron stars or blacks), we begin to probe the different conditions producing these binaries. Most studies of compact remnant formation focus either on stellar collapse from the evolution of field binary stars in gas-free environments or the formation of stars in clusters where dynamical interactions capture the compact objects, forming binaries. But a third scenario exists. In this paper, we study the fate of massive stars formed, accrete gas, and evolve in the dense disks surrounding supermassive black holes. We calculate the explosions produced and compact objects formed by the collapse of these massive stars. Nucleosynthetic yields may provide an ideal, directly observable, diagnostic of the formation and fate of these stars in active galactic nuclei. We present a first study of the explosive yields from these stars, comparing these yields with the observed nucleosynthetic signatures in the disks around supermassive stars with quasars. We show that, even though these stars tend to form black holes, their rapid rotation leads to disks that can eject a considerable amount of iron during the collapse of the star. The nucleosynthetic yields from these stars can produce constraints on the number of systems formed in this manner, but further work is needed to exploit variations from the initial models presented in this paper.