Galaxies SIG Seminar - Monsters in the Dark (Feb 4, 2026)

The Galaxies Science Interest Group seminar on February 4, 2026 featured John Weaver presenting Monsters in the Dark: Searching Far and Wide for Ultra-Luminous Galaxies at Cosmic Dawn. Weaver discussed evidence that the first galaxies (z > 10) appear to have formed faster and more efficiently than standard models predict and argued that studying the brightest analogues at z ~ 7–9 is a practical alternative.

He presented 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, and described how these rare systems constrain the extreme tip of the UV luminosity function.

The talk previewed morphologies, assembly histories, and spatially-resolved properties of a luminous z ~ 8 galaxy observed with NIRSpec/IFU and emphasized the need for spatially-resolved spectroscopy to interpret the thousands of similar galaxies that will be discovered by Euclid and Roman.

john weaver, monsters in the dark, ultra-luminous galaxies, cosmic dawn, epoch of reionization, muv -24, gnz-11, euclid deep fields, nirspec ifu, spatially-resolved spectroscopy