Unveiling galaxy chemical enrichment mechanisms out to z~8 from direct determination of O & Ar abundances from JWST/NIRSPEC spectroscopy

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Main Authors: Bhattacharya, Souradeep, Arnaboldi, Magda, Gerhard, Ortwin, Kobayashi, Chiaki, Saha, Kanak
Format: Preprint
Published: 2024
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author Bhattacharya, Souradeep
Arnaboldi, Magda
Gerhard, Ortwin
Kobayashi, Chiaki
Saha, Kanak
author_facet Bhattacharya, Souradeep
Arnaboldi, Magda
Gerhard, Ortwin
Kobayashi, Chiaki
Saha, Kanak
contents Galaxy chemical enrichment mechanisms have primarily been constrained by [$α$/Fe] and [Fe/H] measurements of individual stars and integrated light from stellar populations. However such measurements are limited at higher redshifts (z>1). Recently, we proposed an analogous diagram of the oxygen-to-argon abundance ratio, log(O/Ar), vs Ar abundance, 12+log(Ar/H), as a new diagnostic window for emission nebulae. In this Letter, using robust line flux measurements including temperature sensitive auroral lines, we present direct determination of O and Ar abundances in nine SFGs from JWST/NIRSPEC spectra at z$\sim$1.3-7.7, and two more with Keck/MOSFIRE spectra at z$\sim$2.2. Utilising their positions on the log(O/Ar) vs 12+log(Ar/H) plane, we present the first inference of galaxy chemical enrichment mechanisms from an ensemble of galaxies. The SFGs at z$\sim$1.3-3.4 are consistent with the solar neighbourhood galactic chemical enrichment models of the Milky Way Galaxy that are driven by core-collapse and Type Ia supernovae. Such enrichment mechanisms thus occur at least out to z$\sim$3.4. However, the highest-redshift SFGs (z$\sim$3.6-7.7) have very low log(O/Ar) values, revealing a different enrichment process at z>3.6. Such low log(O/Ar) values may be caused by a rapid but intermittent star-formation and/or additional sources. The new diagnostic window for SFGs enables us to reveal the unique fingerprints of galaxy chemical enrichment out to cosmic dawn.
format Preprint
id arxiv_https___arxiv_org_abs_2408_13396
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Unveiling galaxy chemical enrichment mechanisms out to z~8 from direct determination of O & Ar abundances from JWST/NIRSPEC spectroscopy
Bhattacharya, Souradeep
Arnaboldi, Magda
Gerhard, Ortwin
Kobayashi, Chiaki
Saha, Kanak
Astrophysics of Galaxies
Galaxy chemical enrichment mechanisms have primarily been constrained by [$α$/Fe] and [Fe/H] measurements of individual stars and integrated light from stellar populations. However such measurements are limited at higher redshifts (z>1). Recently, we proposed an analogous diagram of the oxygen-to-argon abundance ratio, log(O/Ar), vs Ar abundance, 12+log(Ar/H), as a new diagnostic window for emission nebulae. In this Letter, using robust line flux measurements including temperature sensitive auroral lines, we present direct determination of O and Ar abundances in nine SFGs from JWST/NIRSPEC spectra at z$\sim$1.3-7.7, and two more with Keck/MOSFIRE spectra at z$\sim$2.2. Utilising their positions on the log(O/Ar) vs 12+log(Ar/H) plane, we present the first inference of galaxy chemical enrichment mechanisms from an ensemble of galaxies. The SFGs at z$\sim$1.3-3.4 are consistent with the solar neighbourhood galactic chemical enrichment models of the Milky Way Galaxy that are driven by core-collapse and Type Ia supernovae. Such enrichment mechanisms thus occur at least out to z$\sim$3.4. However, the highest-redshift SFGs (z$\sim$3.6-7.7) have very low log(O/Ar) values, revealing a different enrichment process at z>3.6. Such low log(O/Ar) values may be caused by a rapid but intermittent star-formation and/or additional sources. The new diagnostic window for SFGs enables us to reveal the unique fingerprints of galaxy chemical enrichment out to cosmic dawn.
title Unveiling galaxy chemical enrichment mechanisms out to z~8 from direct determination of O & Ar abundances from JWST/NIRSPEC spectroscopy
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2408.13396