DESI Emission Line Galaxies: Redshift Surveys of the 2020s

Emission Line Galaxies (ELGs) are abundant at z=1-2 and today's experiments are able to measure their spectroscopic redshift despite their faintness, thanks to the presence of emission lines.

As such, ELGs are a core tracer for this decade cosmological experiments dedicated to large spectroscopic surveys (DESI, Euclid, PFS): half of the DESI spectra will come from the ELGs (17 million spectra).

We will present this DESI ELG sample, how it has been selected, and its spectroscopic properties from DESI observations since Dec. 2020, which already observed several millions of ELG spectra.