[Paper Review] Detection of [OIII]88$μ$m in JADES-GS-z14-0 at z=14.1793

Sander Schouws, R. J. Bouwens+14 more|arXiv (Cornell University)|Sep 30, 2024

Medical Imaging Techniques and Applications4 citations

TL;DR

This paper reports the first robust ALMA detection of the [OIII] 88 μm emission line in JADES-GS-z14-0 at z = 14.1793, confirming its spectroscopic redshift with 6.6σ significance and refining it to z = 14.1793 ± 0.0007, a 180× improvement over prior NIRSpec measurements. The detection, achieved in just 2.8 hours of integration, reveals a surprisingly metal-enriched (Z ≈ 0.05–0.2 Z⊙) galaxy with low dust content (Md/M⋆ < 2×10⁻³), indicating rapid early metal enrichment and star formation in the first 300 Myr after the Big Bang.

ABSTRACT

We report the first successful ALMA follow-up observations of a secure $z &gt; 10$ JWST-selected galaxy, by robustly detecting ($6.6σ$) the [OIII]$_{88μm}\,$ line in JADES-GS-z14-0 (hereafter GS-z14). The ALMA detection yields a spectroscopic redshift of $z=14.1793\pm0.0007$, and increases the precision on the prior redshift measurement of $z=14.32_{-0.20}^{+0.08}$ from NIRSpec by $\gtrsim$180$ imes$. Moreover, the redshift is consistent with that previously determined from a tentative detection ($3.6σ$) of CIII]$_{1907,1909}$ ($z=14.178\pm0.013$), solidifying the redshift determination via multiple line detections. We measure a line luminosity of $L_\mathrm{[OIII]88} = (2.1 \pm 0.5) imes10^8\,L_\odot$, placing GS-z14 at the lower end, but within the scatter of, the local $L_\mathrm{[OIII]88}$-star formation rate relation. No dust continuum from GS-z14 is detected, suggesting an upper limit on the dust-to-stellar mass ratio of $&lt; 2 imes 10^{-3}$, consistent with dust production from supernovae with a yield $y_d &lt; 0.3\,M_\odot$. Combining a previous JWST/MIRI photometric measurement of the [OIII]$λλ$4959,5007$\mathrm{\mathring{A}}$ and H$β$ lines with Cloudy models, we find GS-z14 to be surprisingly metal-enriched ($Z\sim0.05 - 0.2\,Z_\odot$) a mere $300\,\mathrm{Myr}$ after the Big Bang. The detection of a bright oxygen line in GS-z14 thus reinforces the notion that galaxies in the early Universe undergo rapid evolution.

Motivation & Objective

• To secure a precise spectroscopic redshift for JADES-GS-z14-0, a z > 10 galaxy identified by JWST, using ALMA follow-up observations.
• To test the robustness of the prior NIRSpec redshift measurement (z = 14.32⁻⁰.²⁰⁺⁰.⁰⁸) through independent far-infrared line detection.
• To constrain the physical conditions in GS-z14-0, including metallicity, dust content, and ionization state, via multi-wavelength line analysis.
• To assess the galaxy’s star formation rate, dynamical mass, and metal enrichment history in the context of early cosmic evolution models.
• To evaluate the feasibility of ALMA for detecting high-redshift emission lines in faint, distant galaxies with high precision.

Proposed method

• Conducted a 2.8-hour ALMA Cycle-10 Director’s Discretionary Time (DDT) observation in Band 6, covering 218.70–229.45 GHz to probe redshifts z = 13.79 to 14.51.
• Performed a spectral scan centered on the expected [OIII] 88 μm line at 223.528 ± 0.009 GHz, detecting a 6.6σ emission line in JADES-GS-z14-0.
• Calibrated the redshift using the observed line frequency and rest-frame wavelength, yielding z = 14.1793 ± 0.0007.
• Combined the ALMA [OIII] 88 μm detection with prior JWST/MIRI photometry of [OIII] λλ4959,5007Å and Hβ to derive metallicity using Cloudy photoionization models.
• Set a 3σ upper limit on the 90 μm dust continuum flux (≤15.1 μJy/beam), enabling constraints on the dust-to-stellar mass ratio.
• Used the line width (FWHM = 136 ± 31 km s⁻¹) and dynamical mass estimate (1.0 ± 0.5) × 10⁹ M⊙ (sin i)² to infer kinematic and structural properties.

Figure 1: Left Panel: The ALMA observations cover 98% of the redshift probability distribution derived from the Lyman break as observed by NIRSpec PRISM. We use two tunings with three spectral windows each, tuning 1 and 2 cover 83% and 15% of the probability distribution respectively. Right Panel: F

Experimental results

Research questions

• RQ1 Can the [OIII] 88 μm emission line be robustly detected in a z > 14 galaxy using ALMA, and what does this reveal about its redshift and physical state?
• RQ2 How does the ALMA-derived spectroscopic redshift of GS-z14-0 compare to the prior NIRSpec measurement, and what is the improvement in precision?
• RQ3 What is the metallicity of GS-z14-0, and how does it compare to expectations for a galaxy only 300 Myr after the Big Bang?
• RQ4 What constraints can be placed on the dust content and dust production efficiency in GS-z14-0 based on the non-detection of its 90 μm continuum?
• RQ5 How do the multi-wavelength line detections ([OIII] 88 μm, CIII] 1907,1909, and UV-optical lines) collectively support the redshift and physical interpretation of GS-z14-0?

Key findings

• A robust 6.6σ detection of the [OIII] 88 μm line was achieved in just 2.8 hours of ALMA integration, yielding a spectroscopic redshift of z = 14.1793 ± 0.0007, a 180× improvement in precision over the prior NIRSpec measurement.
• The redshift is consistent with the 3.6σ tentative detection of CIII] 1907,1909 at z = 14.178 ± 0.013, confirming the reliability of the high-redshift identification.
• The [OIII] 88 μm line luminosity is measured at (2.1 ± 0.5) × 10⁸ L⊙, placing GS-z14 within the scatter of the local [OIII] 88 μm–star formation rate relation.
• No dust continuum is detected at 90 μm, setting a 3σ upper limit of 15.1 μJy/beam, implying a dust-to-stellar mass ratio Md/M⋆ < 2 × 10⁻³, consistent with supernova dust yields yd < 0.3 M⊙ per SN.
• Combining ALMA and JWST/MIRI data with Cloudy models indicates GS-z14-0 has a surprisingly high metallicity of Z ≈ 0.05–0.2 Z⊙, despite forming only 300 Myr after the Big Bang.
• The galaxy’s dynamical mass is estimated at (1.0 ± 0.5) × 10⁹ M⊙ (sin i)², with a line width of 136 ± 31 km s⁻¹, suggesting a compact, dynamically hot system with ongoing intense star formation.

Figure 2: Detection of [OIII] ${}_{88\mu m}\,$ in GS-z14 at $z=14.1793\pm 0.0007$ . Left Panel: Contours showing the [OIII] ${}_{88\mu m}\,$ emission (2, 3, 4 and 5 $\sigma$ ) overlaid on the F200W imaging (Eisenstein et al., 2023a , b ) . The [OIII] ${}_{88\mu m}\,$ emission is detected at a peak s