Spectroscopic Assessment of ODIN Lyman Alpha Emitter Candidates

Star formation causes galaxies to emit Lyman Alpha photons. Lyman Alpha Emitters (LAEs) are young, low-mass galaxies whose Lyman Alpha emission is not blocked by interstellar dust, enabling them to be observed by large telescopes. The LAEs that we study are located in the distant universe at redshifts of z=2.4, 3.1, and 4.5. These redshifts correspond to a point in the universe’s history called Cosmic Noon, where the pace of galaxy assembly peaked and some galaxies started to clump into clusters within the universe’s large scale structure. Understanding LAEs thus helps us to understand the distribution of matter in the universe. For this work, we select LAE candidates from the ODIN (One-hundred-deg^2 DECam Imaging in Narrowbands) project. As described Lee et al. 2023 (arXiv:2309.10191), ODIN has signed an inter-collaboration agreement with DESI (the Dark Energy Spectroscopic Instrument). This allows us to compare ODIN LAE candidate samples with large spectroscopic catalogs obtained by DESI to validate the samples. DESI has directly targeted thousands of ODIN LAE candidates in the COSMOS and XMM-LSS fields, yielding over 5000 confirmed redshifts. We compile these redshifts and use them to determine the contamination rate, completeness, and redshift distribution of ODIN LAE samples.