Stellar Evolution in the Disks of Active Galactic Nuclei Produces
  Rapidly Rotating Massive Stars
  Stars can either be formed in or captured by the accretion disks in Active
Galactic Nuclei (AGN). These AGN stars are irradiated and subject to extreme
levels of accretion, which can turn even low-mass stars into very massive ones
($M > 100 {\rm M}_\odot$) whose evolution may result in the formation of
massive compact objects ($M > 10 {\rm M}_\odot$). Here we explore the spins of
these AGN stars and the remnants they leave behind. We find that AGN stars
rapidly spin up via accretion, eventually reaching near-critical rotation
rates. They further maintain near-critical rotation even as they shed their
envelopes, become compact, and undergo late stages of burning. This makes them
good candidates to produce high-spin massive black holes, such as the ones seen
by LIGO-Virgo in GW190521g, as well as long Gamma Ray Bursts (GRBs) and the
associated chemical pollution of the AGN disk.
