Kavli Affiliate: Roberto Maiolino
| First 5 Authors: Francesco D’Eugenio, Roberto Maiolino, Stefano Carniani, Emma Curtis-Lake, Joris Witstok
| Summary:
Finding the emergence of the first generation of metals in the early
Universe, and identifying their origin, are some of the most important goals of
modern astrophysics. We present deep JWST/NIRSpec spectroscopy of GS-z12, a
galaxy at z=12.5, in which we report the detection of C
III]${lambda}{lambda}$1907,1909 nebular emission. This is the most distant
detection of a metal transition and the most distant redshift determination via
emission lines. In addition, we report tentative detections of [O
II]${lambda}{lambda}$3726,3729 and [Ne III]${lambda}$3869, and possibly O
III]${lambda}{lambda}$1661,1666. By using the accurate redshift from C III],
we can model the Ly${alpha}$ drop to reliably measure an absorbing column
density of hydrogen of $N_{HI} approx 10^{22}$ cm$^{-2}$ – too high for an IGM
origin and implying abundant ISM in GS-z12 or CGM around it. We infer a lower
limit for the neutral gas mass of about $10^7$ MSun which, compared with a
stellar mass of $approx4 times 10^7$ MSun inferred from the continuum
fitting, implies a gas fraction higher than about 0.1-0.5. We derive a solar or
even super-solar carbon-to-oxygen ratio, tentatively [C/O]>0.15. This is higher
than the C/O measured in galaxies discovered by JWST at z=6-9, and higher than
the C/O arising from Type-II supernovae enrichment, while AGB stars cannot
contribute to carbon enrichment at these early epochs and low metallicities.
Such a high C/O in a galaxy observed 350 Myr after the Big Bang may be
explained by the yields of extremely metal poor stars, and may even be the
heritage of the first generation of supernovae from Population III progenitors.
| Search Query: ArXiv Query: search_query=au:”Roberto Maiolino”&id_list=&start=0&max_results=3