We analyse the chemical properties of three z~8 galaxies behind the galaxy
cluster SMACS J0723.3-7327, observed as part of the Early Release Observations
programme of the James Webb Space Telescope (JWST). Exploiting O III4363
auroral line detections in NIRSpec spectra, we robustly apply the direct Te
method for the very first time at such high redshift, measuring metallicities
ranging from extremely metal poor (12+log(O/H)~7) to about one-third solar. We
also discuss the excitation properties of these sources, and compare them with
local strong-line metallicity calibrations. We find that none of the considered
diagnostics match simultaneously the observed relations between metallicity and
strong-line ratios for the three sources, implying that a proper re-assessment
of the calibrations may be needed at these redshifts. On the mass-metallicity
plane, the two galaxies at z~7.6 (log(M*/M_sun) = 8.1, 8.7) have metallicities
that are consistent with the extrapolation of the mass-metallicity relation at
z~2-3, while the least massive galaxy at z~8.5 (log(M*/M_sun) = 7.8) shows
instead a significantly lower metallicity . The three galaxies show different
level of offset relative to the Fundamental Metallicity Relation, with two of
them (at z~7.6) being marginally consistent, while the z~8.5 source deviating
significantly, being probably far from the smooth equilibrium between gas
flows, star formation and metal enrichment in place at later epochs.
Описание
The chemical enrichment in the early Universe as probed by JWST via direct metallicity measurements at z~8
%0 Generic
%1 curti2022chemical
%A Curti, M.
%A D'Eugenio, F.
%A Carniani, S.
%A Maiolino, R.
%A Sandles, L.
%A Witstok, J.
%A Baker, W. M.
%A Bennett, J. S.
%A Piotrowska, J. M.
%A Tacchella, S.
%A Charlot, S.
%A Nakajima, K.
%A Maheson, G.
%A Mannucci, F.
%A Arribas, S.
%A Belfiore, F.
%A Bonaventura, N. R.
%A Bunker, A. J.
%A Chevallard, J.
%A Cresci, G.
%A Curtis-Lake, E.
%A Hayden-Pawson, C.
%A Kumari, N.
%A Laseter, I.
%A Looser, T. J.
%A Marconi, A.
%A Maseda, M. V.
%A Jones, G. C.
%A Scholtz, J.
%A Smit, R.
%A Ubler, H.
%A Wallace, I. E. B.
%D 2022
%K library
%T The chemical enrichment in the early Universe as probed by JWST via
direct metallicity measurements at z~8
%U http://arxiv.org/abs/2207.12375
%X We analyse the chemical properties of three z~8 galaxies behind the galaxy
cluster SMACS J0723.3-7327, observed as part of the Early Release Observations
programme of the James Webb Space Telescope (JWST). Exploiting O III4363
auroral line detections in NIRSpec spectra, we robustly apply the direct Te
method for the very first time at such high redshift, measuring metallicities
ranging from extremely metal poor (12+log(O/H)~7) to about one-third solar. We
also discuss the excitation properties of these sources, and compare them with
local strong-line metallicity calibrations. We find that none of the considered
diagnostics match simultaneously the observed relations between metallicity and
strong-line ratios for the three sources, implying that a proper re-assessment
of the calibrations may be needed at these redshifts. On the mass-metallicity
plane, the two galaxies at z~7.6 (log(M*/M_sun) = 8.1, 8.7) have metallicities
that are consistent with the extrapolation of the mass-metallicity relation at
z~2-3, while the least massive galaxy at z~8.5 (log(M*/M_sun) = 7.8) shows
instead a significantly lower metallicity . The three galaxies show different
level of offset relative to the Fundamental Metallicity Relation, with two of
them (at z~7.6) being marginally consistent, while the z~8.5 source deviating
significantly, being probably far from the smooth equilibrium between gas
flows, star formation and metal enrichment in place at later epochs.
@misc{curti2022chemical,
abstract = {We analyse the chemical properties of three z~8 galaxies behind the galaxy
cluster SMACS J0723.3-7327, observed as part of the Early Release Observations
programme of the James Webb Space Telescope (JWST). Exploiting [O III]4363
auroral line detections in NIRSpec spectra, we robustly apply the direct Te
method for the very first time at such high redshift, measuring metallicities
ranging from extremely metal poor (12+log(O/H)~7) to about one-third solar. We
also discuss the excitation properties of these sources, and compare them with
local strong-line metallicity calibrations. We find that none of the considered
diagnostics match simultaneously the observed relations between metallicity and
strong-line ratios for the three sources, implying that a proper re-assessment
of the calibrations may be needed at these redshifts. On the mass-metallicity
plane, the two galaxies at z~7.6 (log(M*/M_sun) = 8.1, 8.7) have metallicities
that are consistent with the extrapolation of the mass-metallicity relation at
z~2-3, while the least massive galaxy at z~8.5 (log(M*/M_sun) = 7.8) shows
instead a significantly lower metallicity . The three galaxies show different
level of offset relative to the Fundamental Metallicity Relation, with two of
them (at z~7.6) being marginally consistent, while the z~8.5 source deviating
significantly, being probably far from the smooth equilibrium between gas
flows, star formation and metal enrichment in place at later epochs.},
added-at = {2022-07-26T11:06:40.000+0200},
author = {Curti, M. and D'Eugenio, F. and Carniani, S. and Maiolino, R. and Sandles, L. and Witstok, J. and Baker, W. M. and Bennett, J. S. and Piotrowska, J. M. and Tacchella, S. and Charlot, S. and Nakajima, K. and Maheson, G. and Mannucci, F. and Arribas, S. and Belfiore, F. and Bonaventura, N. R. and Bunker, A. J. and Chevallard, J. and Cresci, G. and Curtis-Lake, E. and Hayden-Pawson, C. and Kumari, N. and Laseter, I. and Looser, T. J. and Marconi, A. and Maseda, M. V. and Jones, G. C. and Scholtz, J. and Smit, R. and Ubler, H. and Wallace, I. E. B.},
biburl = {https://www.bibsonomy.org/bibtex/2f7c235883bb7ccb49943564848960178/gpkulkarni},
description = {The chemical enrichment in the early Universe as probed by JWST via direct metallicity measurements at z~8},
interhash = {85eeb31c06f2e44cb4e8b84fe5b32020},
intrahash = {f7c235883bb7ccb49943564848960178},
keywords = {library},
note = {cite arxiv:2207.12375Comment: 13 pages, 7 figures},
timestamp = {2022-07-26T11:06:40.000+0200},
title = {The chemical enrichment in the early Universe as probed by JWST via
direct metallicity measurements at z~8},
url = {http://arxiv.org/abs/2207.12375},
year = 2022
}