TY - JOUR
T1 - Nitrogen enhancements 440 Myr after the big bang: supersolar N/O, a tidal disruption event, or a dense stellar cluster in GN-z11?
AU - Cameron, Alex J.
AU - Katz, Harley B.
AU - Rey, Martin P.
AU - Saxena, Aayush
PY - 2023/8/31
Y1 - 2023/8/31
N2 - Recent observations of GN-z11 with JWST/NIRSpec revealed numerous oxygen, carbon, nitrogen, and helium emission lines at z = 10.6. Using the measured line fluxes, we derive abundance ratios of individual elements within the interstellar medium (ISM) of this superluminous galaxy. Driven by the unusually-bright N III] λ1750 and N IV] λ1486 emission lines (and by comparison, faint O III] λλ1660, 1666 lines), our fiducial model prefers log (N/O) > -0.25, greater than four times solar and in stark contrast to lower-redshift star-forming galaxies. The derived log (C/O) > -0.78, (≈30 per cent solar) is also elevated with respect to galaxies of similar metallicity (12 + log (O/H) ≈ 7.82), although less at odds with lower-redshift measurements. We explore the feasibility of achieving these abundance ratios via several enrichment mechanisms using metal yields available in the literature. Given the long time-scale typically expected to enrich nitrogen with stellar winds, traditional scenarios require a very fine-tuned formation history to reproduce such an elevated N/O. We find no compelling evidence that nitrogen enhancement in GN-z11 can be explained by enrichment from metal-free Population III stars. Interestingly, yields from runaway stellar collisions in a dense stellar cluster or a tidal disruption event provide promising solutions to give rise to these unusual emission lines at z = 10.6, and explain the resemblance between GN-z11 and a nitrogen-loud quasar. These recent observations showcase the new frontier opened by JWST to constrain galactic enrichment and stellar evolution within 440 Myr of the big bang....
AB - Recent observations of GN-z11 with JWST/NIRSpec revealed numerous oxygen, carbon, nitrogen, and helium emission lines at z = 10.6. Using the measured line fluxes, we derive abundance ratios of individual elements within the interstellar medium (ISM) of this superluminous galaxy. Driven by the unusually-bright N III] λ1750 and N IV] λ1486 emission lines (and by comparison, faint O III] λλ1660, 1666 lines), our fiducial model prefers log (N/O) > -0.25, greater than four times solar and in stark contrast to lower-redshift star-forming galaxies. The derived log (C/O) > -0.78, (≈30 per cent solar) is also elevated with respect to galaxies of similar metallicity (12 + log (O/H) ≈ 7.82), although less at odds with lower-redshift measurements. We explore the feasibility of achieving these abundance ratios via several enrichment mechanisms using metal yields available in the literature. Given the long time-scale typically expected to enrich nitrogen with stellar winds, traditional scenarios require a very fine-tuned formation history to reproduce such an elevated N/O. We find no compelling evidence that nitrogen enhancement in GN-z11 can be explained by enrichment from metal-free Population III stars. Interestingly, yields from runaway stellar collisions in a dense stellar cluster or a tidal disruption event provide promising solutions to give rise to these unusual emission lines at z = 10.6, and explain the resemblance between GN-z11 and a nitrogen-loud quasar. These recent observations showcase the new frontier opened by JWST to constrain galactic enrichment and stellar evolution within 440 Myr of the big bang....
U2 - 10.1093/mnras/stad1579
DO - 10.1093/mnras/stad1579
M3 - Article
SN - 0035-8711
JO - Monthly Notices of the Royal Astronomical Society
JF - Monthly Notices of the Royal Astronomical Society
ER -