The most distant galaxy observed by the Hubble Space Telescope is called GN-z11, as it was observed in the GOODS-North field with a photometric redshift of z = 11.1 (we see it when the universe was about 400 million years old). The NIRSpec spectroscope on the James Webb Space Telescope has estimated a spectrometric redshift of z = 10.6034 ± 0.0013 (when the universe was about 430 million years old). Multiple emission lines are observed, such as the usual [O ii] 3727, [Ne iii] 3869, and [C iii] 1909, and the rare [N iv] 1486 and [N iii] 1748, which imply high ionization. Its origin may be the activity of its supermassive black hole (active galactic nucleus) or a high rate of star formation (which in its case is estimated at ∼20–30 M☉/yr, solar masses per year).
The JADES (JWST Advanced Deep Extragalactic Survey) project also publishes the observations obtained with NIRCam (which includes a photometric redshift estimate of 10.60). GN-z11 is estimated to have a stellar mass of ∼10⁹ M☉, with a star formation rate of ∼20 M☉/yr, and a young stellar population with a mean age of ∼20 Myr. It is also observed that its nucleus is very compact. Galaxy formation models predict that these types of galaxies have to be observed in compact galaxy clusters; 9 nearby faint galaxies (within ∼5 Mpc) are observed in the JWST images with photometric redshifts consistent with z=10.6. Its future spectroscopic observation will surely offer us a lot of relevant information.
The discovery of GN-z11 was published in 2016 (Astrophysical Journal). GN-z11 made headlines in October 2021 thanks to a 245-second long-duration gamma-ray burst (GRB) (Nature Astronomy) that raised many questions; some astronomers considered it so unlikely that they proposed that an artificial object (a satellite) was responsible for the observed signal (LCMF, 29 Oct 2021). The spectrum observed by JWST resolves the controversy since it shows a great ionization, which could well be the product of the intense activity of its supermassive black hole, responsible for the observed GRB. Undoubtedly GN-z11 (which can keep its name since 10.6 rounds to 11) is a much rarer early galaxy than previously thought. see
Two new papers have been published on arXiv (submitted to A&A and ApJ): Andrew J. Bunker, Aayush Saxena, …, Lily Whitler, “JADES NIRSpec Spectroscopy of GN-z11: Lyman-α emission and possible enhanced nitrogen abundance in a z= 10.60 luminous galaxy,” arXiv:2302.07256 [astro-ph.GA] (14 Feb 2023), doi: https://doi.org/10.48550/arXiv.2302.07256; Sandro Tacchella, Daniel J. Eisenstein, …, Lily Whitler, “JADES Imaging of GN-z11: Revealing the Morphology and Environment of a Luminous Galaxy 430 Myr After the Big Bang,” arXiv:2302.07234 [astro-ph.GA] (14 Feb 2023), doi:
https://doi.org/10.48550/arXiv.2302.07234.