Spectroscopic confirmation of two luminous galaxies at a redshift of 14

The first observations of the James Webb Space Telescope (JWST) have revolutionized our understanding of the Universe by identifying galaxies at redshift $z \approx 13$ . In addition, the discovery of many luminous galaxies at Cosmic Dawn ($z > 10$ ) has suggested that galaxies developed rapidly, in apparent tension with many standard models. However, most of these galaxies lack spectroscopic confirmation, so their distances and properties are uncertain. Here we present JWST Advanced Deep Extragalactic Survey–Near-Infrared Spectrograph spectroscopic confirmation of two luminous galaxies at $z = 14.32_{-0.20}^{+0.08}$ and $z = 13.90 \pm 0.17$ . The spectra reveal ultraviolet continua with prominent $\mathrm{Lyman}-\alpha$ breaks but no detected emission lines. This discovery proves that luminous galaxies were already in place $300$ million years after the Big Bang and are more common than what was expected before JWST. The most distant of the two galaxies is unexpectedly luminous and is spatially resolved with a radius of $260\ \mathrm{parsecs}$ . Considering also the very steep ultraviolet slope of the second galaxy, we conclude that both are dominated by stellar continuum emission, showing that the excess of luminous galaxies in the early Universe cannot be entirely explained by accretion onto black holes. Galaxy formation models will need to address the existence of such large and luminous galaxies so early in cosmic history.

Nature, Volume 633, Issue 8029, pages 318-322