The Astrophysical Journal (Jan 2025)

Carbon and Iron Deficiencies in Quiescent Galaxies at z = 1–3 from JWST-SUSPENSE: Implications for the Formation Histories of Massive Galaxies

  • Aliza G. Beverage,
  • Martje Slob,
  • Mariska Kriek,
  • Charlie Conroy,
  • Guillermo Barro,
  • Rachel Bezanson,
  • Gabriel Brammer,
  • Chloe M. Cheng,
  • Anna de Graaff,
  • Natascha M. Förster Schreiber,
  • Marijn Franx,
  • Brian Lorenz,
  • Pavel E. Mancera Piña,
  • Danilo Marchesini,
  • Adam Muzzin,
  • Andrew B. Newman,
  • Sedona H. Price,
  • Alice E. Shapley,
  • Mauro Stefanon,
  • Katherine A. Suess,
  • Pieter van Dokkum,
  • David Weinberg,
  • Daniel R. Weisz

DOI
https://doi.org/10.3847/1538-4357/ad96b6
Journal volume & issue
Vol. 979, no. 2
p. 249

Abstract

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We present the stellar metallicities and multielement abundances (C, Mg, Si, Ca, Ti, Cr, and Fe) of 15 massive (log M / M _⊙ = 10.2–11.2) quiescent galaxies at z = 1–3, derived from ultradeep JWST-SUSPENSE spectra. Compared to quiescent galaxies at z ∼ 0, these galaxies exhibit a deficiency of 0.26 ± 0.04 dex in [C/H], 0.16 ± 0.03 dex in [Fe/H], and 0.07 ± 0.04 dex in [Mg/H], implying rapid formation and quenching before significant enrichment from asymptotic giant branch stars and Type Ia supernovae. Additionally, we find that galaxies forming at higher redshift consistently show higher [Mg/Fe] and lower [Fe/H] and [Mg/H], regardless of their observed redshift. The evolution in [Fe/H] and [C/H] is therefore primarily driven by lower-redshift samples naturally including galaxies with longer star formation timescales. In contrast, the lower [Mg/H] likely reflects earlier-forming galaxies expelling larger gas reservoirs during their quenching phase. Consequently, the mass–metallicity relation, primarily reflecting [Mg/H], is somewhat lower at z = 1–3 compared to the lower-redshift relation. Finally, we compare our results to standard stellar population modeling approaches employing solar abundance patterns and nonparametric star formation histories (using Prospector ). Our simple stellar population (SSP)-equivalent ages agree with the mass-weighted ages from Prospector , while the metallicities disagree significantly. Nonetheless, the metallicities better reflect [Fe/H] than total [ Z /H]. We also find that the star formation timescales inferred from elemental abundances are significantly shorter than those from Prospector , and we discuss the resulting implications for the early formation of massive galaxies.

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