Kavli Affiliate: Roberto Maiolino
| First 5 Authors: Stefano Carniani, Francesco D’Eugenio, Xihan Ji, Eleonora Parlanti, Jan Scholtz
| Summary:
JADES-GS-z14-0 is the most distant spectroscopically confirmed galaxy yet, at
$z>14$. With a UV magnitude of -20.81, it is one of the most luminous galaxies
at cosmic dawn and its half-light radius of 260 pc means that stars dominate
the observed UV emission. We report ALMA detection of [OIII]88$mu$m line
emission with a significance of 6.67$sigma$ and at a frequency of 223.524~GHz,
corresponding to a redshift of $14.1796pm0.0007$, which is consistent with the
candidate CIII] line detected in the NIRSpec spectrum. At this spectroscopic
redshift, the Lyman-$alpha$ break identified with NIRSpec requires a damped
Lyman-$alpha$ absorber with a column density of $log(N_{rm
HI}/mathrm{cm}^{-2})=21.96$. The total [O,{sc iii}]88$mu$m luminosity
(log$(L_{rm [OIII]}/L_odot) = 8.3pm 0.1$) is fully consistent with the local
$L_{rm [OIII]}-SFR$ relation and indicating a gas-phase metallicity $>0.1~{rm
Z_{rm odot}}$. Using texttt{prospector} SED modeling and combining the ALMA
data with JWST observations, we find $Z=0.17~{rm Z_{rm odot}}$ and a
non-zero escape fraction of ionizing photons ($sim11%$), which is necessary
by the code to reproduce the UV spectrum. We measure an ${rm [O
III]}5007$r{A}/[O III]88$mu$m line flux ratio between 1 and 20, resulting in
an upper limit to the electron density of roughly 700 cm$^{-3}$ assuming a
single-cloud photoionization model. The [OIIII]88$mu$m emission line is
spectrally resolved, with a FWHM of 100 km/s, resulting in a dynamical mass of
log($M_{rm dyn}/M_odot$) = 9.0$pm0.2$. When compared to the stellar mass,
this value represents a conservative upper limit on the gas mass fraction,
which ranges from 50% to 80%, depending on the assumed star formation
history. Past radiation-driven outflows may have cleared the galaxy from the
gas, reducing the gas fraction and thus increasing the escape fraction of
ionizing photons.
| Search Query: ArXiv Query: search_query=au:”Roberto Maiolino”&id_list=&start=0&max_results=3