On the origins of oxygen: ALMA and JWST characterise the multi-phase, metal-enriched, star-bursting medium within a ‘normal’ <a:math xmlns:a="http://www.w3.org/1998/Math/MathML"> <a:mi>z</a:mi> <a:mo>&gt;</a:mo> <a:mn>11</a:mn> </a:math> galaxy

The unexpectedly high abundance of galaxies at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:mi>z</mml:mi> <mml:mo>&gt;</mml:mo> <mml:mn>11</mml:mn> </mml:mrow> </mml:math> revealed by JWST has sparked a debate on the nature of early galaxies and the physical mechanisms regulating their formation. The Atacama Large Millimeter/submillimeter Array (ALMA) has begun to provide vital insights on their gas and dust content, but so far only for extreme ‘blue monsters’. Here we present new, deep ALMA observations of JADES-GS-z11-0, a more typical (sub- <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:msup> <mml:mi>L</mml:mi> <mml:mo>*</mml:mo> </mml:msup> </mml:math> ) <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:mi>z</mml:mi> <mml:mo>&gt;</mml:mo> <mml:mn>11</mml:mn> </mml:mrow> </mml:math> galaxy that bridges the discovery space of JWST and the Hubble Space Telescope. These data confirm the presence of the [O III] 88 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi>μ</mml:mi> </mml:math> m line at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:mn>4.5</mml:mn> <mml:mi>σ</mml:mi> </mml:mrow> </mml:math> significance, precisely at the redshift of several faint emission lines previously seen with JWST/NIRSpec, while the underlying dust continuum remains undetected ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:msub> <mml:mi>F</mml:mi> <mml:mi>ν</mml:mi> </mml:msub> <mml:mo>&lt;</mml:mo> <mml:mn>9.0</mml:mn> <mml:mspace width="0.167em"/> <mml:mrow> <mml:mi mathvariant="normal">μ</mml:mi> <mml:mi mathvariant="normal">J</mml:mi> <mml:mi mathvariant="normal">y</mml:mi> </mml:mrow> </mml:mrow> </mml:math> ), implying an obscured star formation rate (SFR) of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:msub> <mml:mtext mathvariant="normal">SFR</mml:mtext> <mml:mtext mathvariant="normal">IR</mml:mtext> </mml:msub> <mml:mo>≲</mml:mo> <mml:mn>6</mml:mn> <mml:mspace width="0.167em"/> <mml:mrow> <mml:msub> <mml:mi mathvariant="normal">M</mml:mi> <mml:mo mathvariant="normal">⊙</mml:mo> </mml:msub> <mml:mspace width="0.167em"/> <mml:mi mathvariant="normal">y</mml:mi> <mml:msup> <mml:mi mathvariant="normal">r</mml:mi> <mml:mrow> <mml:mo mathvariant="normal">−</mml:mo> <mml:mn mathvariant="normal">1</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:mrow> </mml:math> and dust mass of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:msub> <mml:mi>M</mml:mi> <mml:mtext mathvariant="normal">dust</mml:mtext> </mml:msub> <mml:mo>≲</mml:mo> <mml:mn>1.0</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mn>10</mml:mn> <mml:mn>6</mml:mn> </mml:msup> <mml:mspace width="0.167em"/> <mml:msub> <mml:mi mathvariant="normal">M</mml:mi> <mml:mo mathvariant="normal">⊙</mml:mo> </mml:msub> </mml:mrow> </mml:math> (all <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:mn>3</mml:mn> <mml:mi>σ</mml:mi> </mml:mrow> </mml:math> ). The accurate ALMA redshift of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:msub> <mml:mi>z</mml:mi> <mml:mtext mathvariant="normal">[O III]</mml:mtext> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>11.1221</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.0006</mml:mn> </mml:mrow> </mml:math> ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:mo>≳</mml:mo> <mml:mn>5</mml:mn> <mml:mo>×</mml:mo> </mml:mrow> </mml:math> refined over NIRSpec) helps confirm that redshifts measured purely from the Lyman- <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi>α</mml:mi> </mml:math> break, even spectroscopically, should properly take into account the effects of potential damped Lyman- <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi>α</mml:mi> </mml:math> absorption (DLA) systems to avoid systematic overestimates of up to <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:mi>Δ</mml:mi> <mml:mi>z</mml:mi> <mml:mo>≈</mml:mo> <mml:mn>0.5</mml:mn> </mml:mrow> </mml:math> . The [O III] 88 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mi>μ</mml:mi> </mml:math> m luminosity of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:msub> <mml:mi>L</mml:mi> <mml:mtext mathvariant="normal">[O III]</mml:mtext> </mml:msub> <mml:mo>=</mml:mo> <mml:mrow> <mml:mo stretchy="true" form="prefix">(</mml:mo> <mml:mn>1.1</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.3</mml:mn> <mml:mo stretchy="true" form="postfix">)</mml:mo> </mml:mrow> <mml:mo>×</mml:mo> <mml:msup> <mml:mn>10</mml:mn> <mml:mn>8</mml:mn> </mml:msup> <mml:mspace width="0.167em"/> <mml:msub> <mml:mi mathvariant="normal">L</mml:mi> <mml:mo mathvariant="normal">⊙</mml:mo> </mml:msub> </mml:mrow> </mml:math> , meanwhile, agrees well with the scaling relation for local metal-poor dwarfs given the SFR measured by NIRCam, NIRSpec, and MIRI. The spatially resolved MIRI and ALMA emission also underscores that JADES-GS-z11-0 is likely to consist of two low-mass components that are undergoing strong bursts of star formation yet are already pre-enriched in oxygen ( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"> <mml:mrow> <mml:mo>∼</mml:mo> <mml:mn>30</mml:mn> <mml:mi>%</mml:mi> </mml:mrow> </mml:math> solar), only 400 Myr after the Big Bang.