Astronomers report the spectroscopic confirmation of a red, dust-rich galaxy at a redshift of z = 11.452 ± 0.021. The object, called EGS-z11-R0, was found in public James Webb Space Telescope (JWST) Near-Infrared Spectrograph (NIRSpec) data from the CEERS field. At this distance the light left the galaxy when the universe was only a few hundred million years old, making EGS-z11-R0 the most distant red galaxy confirmed so far.

The team combined low-resolution NIRSpec PRISM spectroscopy (about 13,130 seconds of exposure) and medium-resolution G395M spectroscopy (about 3,130 seconds) with broad-band imaging from the Hubble Space Telescope (HST), JWST NIRCam (Near-Infrared Camera) and MIRI (Mid-Infrared Instrument). They detected rest-frame ultraviolet emission lines, notably C IV (carbon, wavelengths 1548, 1551 Å) and C III] (1908 Å). The positions of these lines give the secure spectroscopic redshift. The spectrum also shows a clear Lyman break, a drop in flux at short wavelengths expected for very distant galaxies.

From fitting the spectrum and the photometry with spectral energy distribution (SED) models, the authors infer a fairly massive and dusty system. Their best-fit estimates are a stellar mass of log(M*/M☉) ≈ 9.2–9.6, a star-formation rate of roughly 10–40 solar masses per year, and substantial dust attenuation with visual extinction AV ≈ 1.2 magnitudes. The galaxy’s ultraviolet slope (βUV) is about −1.0, much redder than the very blue slopes (βUV ≲ −2) seen in most z > 10 galaxies discovered so far.

The emission lines point to a “hard” ionizing radiation field — that is, many high-energy photons. This can be produced by very intense, young star formation, and the line ratios are also compatible with a mix of stars plus a modest contribution from an active galactic nucleus (AGN), meaning an accreting black hole. The main scientific implication is that chemically evolved and dust-enriched galaxies already existed at cosmic dawn. If confirmed for other objects, this would imply rapid production of heavy elements and dust within the first few hundred million years after the Big Bang.