NASA seminar to present ultra‑luminous early galaxies found in Euclid deep fields

NASA's Galaxies Special Interest Group will host a virtual seminar on 4 February 2026 at 1:00pm ET titled "Monsters in the Dark: Searching Far and Wide for Ultra-Luminous Galaxies at Cosmic Dawn," with speaker John Weaver.

The seminar abstract says the first galaxies (z > 10) appear to have formed faster and more efficiently than predicted by standard models, but that these objects are difficult to study and rare. As a next-best option, Weaver will focus on the brightest analogues at more accessible redshifts (z ~ 7–9).

Weaver will present what the abstract describes as the most luminous galaxies yet identified in the epoch of reionization (MUV = –24), about 10 times brighter than GNz-11, unearthed from 50 deg2 of Euclid's Deep Fields. These exceptionally rare and luminous galaxies are said to provide the first constraints on the very tip of the ultraviolet luminosity function, where currently degenerate models can be tested. He will preview morphologies, assembly histories and spatially resolved properties of one of the most luminous z ~ 8 galaxies observed by NIRSpec/IFU.

The abstract says these results underscore the need for spatially resolved spectroscopy to accurately interpret the thousands of similar galaxies that will be discovered by Euclid and Roman. Interested readers are invited to join the seminar.

Key Topics

Science, Euclid, John Weaver, Ultra Luminous Galaxies, Nirspec Ifu