The Astrophysical Journal (Jan 2024)

CEERS Key Paper. VIII. Emission-line Ratios from NIRSpec and NIRCam Wide-Field Slitless Spectroscopy at z > 2

  • Bren E. Backhaus,
  • Jonathan R. Trump,
  • Nor Pirzkal,
  • Guillermo Barro,
  • Steven L. Finkelstein,
  • Pablo Arrabal Haro,
  • Raymond C. Simons,
  • Jessica Wessner,
  • Nikko J. Cleri,
  • Micaela B. Bagley,
  • Michaela Hirschmann,
  • David C. Nicholls,
  • Mark Dickinson,
  • Jeyhan S. Kartaltepe,
  • Casey Papovich,
  • Dale D. Kocevski,
  • Anton M. Koekemoer,
  • Laura Bisigello,
  • Anne E. Jaskot,
  • Ray A. Lucas,
  • Intae Jung,
  • Stephen M. Wilkins,
  • L. Y. Aaron Yung,
  • Henry C. Ferguson,
  • Adriano Fontana,
  • Andrea Grazian,
  • Norman A. Grogin,
  • Lisa J. Kewley,
  • Allison Kirkpatrick,
  • Jennifer M. Lotz,
  • Laura Pentericci,
  • Pablo G. Pérez-González,
  • Swara Ravindranath,
  • Rachel S. Somerville,
  • Guang Yang,
  • Benne W. Holwerda,
  • Peter Kurczynski,
  • Nimish P. Hathi,
  • Caitlin Rose,
  • Kelcey Davis

DOI
https://doi.org/10.3847/1538-4357/ad1520
Journal volume & issue
Vol. 962, no. 2
p. 195

Abstract

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We use James Webb Space Telescope Near-Infrared Camera Wide Field Slitless Spectroscopy (NIRCam WFSS) and the Near-Infrared spectrograph (NIRSpec) in the Cosmic Evolution Early Release survey to measure rest-frame optical emission-line ratios of 155 galaxies at z > 2. The blind NIRCam grism observations include a sample of galaxies with bright emission lines that were not observed on the NIRSpec masks. We study the changes of the H α , [O III ]/H β , and [Ne III ]/[O II ] emission lines in terms of redshift by comparing to lower-redshift SDSS, CLEAR, and MOSDEF samples. We find a significant (>3 σ ) correlation between [O III ]/H β with redshift, while [Ne III ]/[O II ] has a marginal (2 σ ) correlation with redshift. We compare [O III ]/H β and [Ne III ]/[O II ] to stellar mass and H β SFR. We find that both emission-line ratios have a correlation with H β SFR and an anticorrelation with stellar mass across the redshifts 0 < z < 9. Comparison with MAPPINGS V models indicates that these trends are consistent with lower metallicity and higher ionization in low-mass and high-SFR galaxies. We additionally compare to IllustrisTNG predictions and find that they effectively describe the highest [O III ]/H β ratios observed in our sample, without the need to invoke MAPPINGS models with significant shock ionization components.

Keywords