DESI as a survey for galaxy evolution: galaxy scaling relations and the chemical enrichment of galaxies

by Dirk Scholte (Edinburgh)

Wednesday 18 Nov 2026, 14:00 → 15:00 Europe/London

OCW017

Over the past five years, the Dark Energy Spectroscopic Instrument (DESI) has measured spectra of more than 47 million galaxies, the largest spectroscopic sample ever assembled. Although built for cosmology, DESI is also transforming the study of galaxy evolution. I will begin with an overview of DESI as a galaxy evolution survey, based on work from the DESI Galaxy and Quasar Physics Working Group, to show how the selection functions of DESI’s galaxy and quasar samples shape the physical properties we can study. I will then turn to two topics: (1) Galaxy scaling relations over 5 orders of magnitude in stellar mass, with a particular focus on the stellar mass function. (2) How galaxies build up their heavy elements. I will present ‘gold standard’ direct-method chemical abundances for 50,000 galaxies and what they reveal about chemical enrichment. Finally, I will introduce the most metal-poor galaxies in the nearby Universe, which we discovered in DESI Data Release 2, and discuss evidence that these galaxies are puzzlingly gas rich.