Detection of the Far-infrared [O III] and Dust Emission in a Galaxy at Redshift 8.312: Early Metal Enrichment in the Heart of the Reionization Era

Yoichi Tamura, Ken Mawatari, Takuya Hashimoto, Akio K. Inoue, Erik Zackrisson, Lise Christensen, Christian Binggeli, Yuichi Matsuda, Hiroshi Matsuo, Tsutomu T. Takeuchi, Ryosuke S. Asano, Kaho Sunaga, Ikkoh Shimizu, Takashi Okamoto, Naoki Yoshida, Minju M. Lee, Takatoshi Shibuya, Yoshiaki Taniguchi, Hideki Umehata, Bunyo HatsukadeKotaro Kohno, Kazuaki Ota

Research output: Contribution to journalArticlepeer-review

130 Citations (Scopus)

Abstract

We present the Atacama Large Millimeter/submillimeter Array detection of the [O iii] 88 μm line and rest-frame 90 μm dust continuum emission in a Y-dropout Lyman break galaxy (LBG), MACS0416-Y1 lying behind the Frontier Field cluster MACS J0416.1-2403. This [O iii] detection confirms the LBG with a spectroscopic redshift of z = 8.3118 ± 0.0003, making this object one of the farthest galaxies ever identified spectroscopically. The observed 850 μm flux density of 137 ± 26 μJy corresponds to a de-lensed total infrared (IR) luminosity of if assuming a dust temperature of T dust = 50 K and an emissivity index of β = 1.5, yielding a large dust mass of . The ultraviolet-to-far-IR spectral energy distribution modeling where the [O iii] emissivity model is incorporated suggests the presence of a young (τ age ≈ 4 Myr), star-forming ( yr -1 ), moderately metal-polluted (Z ≈ 0.2Z o ) stellar component with a mass of M star = 3 ×10 8 M o . An analytic dust mass evolution model with a single episode of star formation does not reproduce the metallicity and dust mass in τ age ≈ 4 Myr, suggesting a pre-existing evolved stellar component with M star ∼ 3 ×10 9 M and τ age ∼ 0.3 Gyr as the origin of the dust mass.

Original languageEnglish
Article number27
JournalAstrophysical Journal
Volume874
Issue number1
DOIs
Publication statusPublished - 2019 Mar 20
Externally publishedYes

Keywords

  • dust, extinction
  • galaxies: ISM
  • galaxies: formation
  • galaxies: high-redshift

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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