The eventful life of a luminous galaxy at z = 14: metal enrichment, feedback, and low gas fraction?
The eventful life of a luminous galaxy at z = 14: metal enrichment, feedback, and low gas fraction?
Sep 30, 2024·,,,,,,,,,,,,,,,,,,,,,,,,,,
Stefano Carniani
Francesco D'Eugenio
Xihan Ji
Eleonora Parlanti
Jan Scholtz
Fengwu Sun
Giacomo Venturi
Tom J. L. C. Bakx
Mirko Curti
Roberto Maiolino
Sandro Tacchella
Jorge A. Zavala
Kevin Hainline
Joris Witstok
Benjamin D. Johnson
Stacey Alberts
Andrew J. Bunker
Stéphane Charlot
Daniel J. Eisenstein
Jakob M. Helton
Peter Jakobsen
Nimisha Kumari
Brant Robertson
Aayush Saxena
Hannah Übler
Christina C. Williams
Christopher N. A. Willmer
Chris Willott
Abstract
JADES-GS-z14-0 is the most distant spectroscopically confirmed galaxy so far, 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 $260\ \mathrm{pc}$
means that stars dominate the observed UV emission. We report the ALMA detection of $\mathrm{[OIII]}88\mu\mathrm{m}$
line emission with a significance of $6.67\sigma$
and at a frequency of $223.524\ \mathrm{GHz}$
, corresponding to a redshift of $14.1796 \pm 0.0007$
, which is consistent with the candidate $\mathrm{CIII]}$
line detected in the NIRSpec spectrum. At this spectroscopic redshift, the Lyman break identified with NIRSpec requires a damped $\mathrm{Lyman}-\alpha$
absorber with a column density of $\mathrm{log}_{10}(N_{\mathrm{HI}}/\mathrm{cm}^{2}) = 22.23$
. The total $\mathrm{[OIII]}88\mu\mathrm{m}$
luminosity ($\mathrm{log}_{10}(L_{\mathrm{[OIII]}}/L_{\odot}) = 8.3 \pm 0.1$
) is fully consistent with the local $L_{\mathrm{[OIII]}}-\mathrm{SFR}$
relation. Based on the $L_{\mathrm{[OIII]}}/\mathrm{SFR}$
, we infer a gas-phase metallicity $> 0.1\ Z_{\odot}$
, which is somewhat unexpected given the weakness of the UV emission lines. Using prospector SED modeling and combining the ALMA data with JWST observations, we find $Z = 0.17\ Z_{\odot}$
and an escape fraction of ionizing photons of $20\%$
, which is necessary to explain the UV spectrum. We measure an $\mathrm{[OIII]}5007\mathrm{\AA}/\mathrm{[OIII]}88\mu\mathrm{m}$
line flux ratio between $1$
and $10$
, resulting in an upper limit to the electron density of roughly $300\ \mathrm{cm}^{-3}$
, which is lower than those measured in other $\mathrm{high}-z$
luminous galaxies. The $\mathrm{[OIII]}88\mu\mathrm{m}$
emission line is spectrally resolved, with a FWHM of $100\ \mathrm{km/s}$
, resulting in a dynamical mass of $\mathrm{log}_{10}(M_{\mathrm{dyn}}/M_{\odot}) = 9.0 \pm 0.2$
. This value is comparable to the stellar mass derived from the SED fitting, which implies a very low gas fraction. 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.
Type
Publication
eprint arXiv:2409.20533
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