Colloquium- Ashley Ross (OSU)- The Dark Energy Spectroscopic Instrument: Mapping the Structure of the Universe with a Galaxy Redshift Survey

Abstract: The 3D distribution of galaxies encodes a wealth of cosmological information, including on the nature of Dark Energy and the origin of the Universe's structure. The Dark Energy Spectroscopic Instrument (DESI) collaboration is in the process of producing the largest ever map of this distribution by measuring galaxy redshifts. It is just over two years into its five-year survey and has already secured over 20 million redshifts --- a factor of 10 improvement on the total measured before DESI. This unprecedented achievement has been made possible by the ability to simultaneously measure 5000 redshifts at a time, using robots that can dynamically place an optical fiber to an accuracy of 2 microns. I will describe the exciting advances in cosmological information that DESI data provides and what will be left to discover in the experiments that will succeed DESI.