The DESI Spectroscopic Pipeline Performances

The Dark Energy Spectroscopic Instrument (DESI) comprises a focal plane with 5000 robotically actuated fibers feeding 10 spectrographs installed in a thermally controlled room. Each spectrograph is composed of 3 optical arms optimized to cover the wavelength range accessible from the ground with CCDs, from 360 to 980nm, with a spectral resolution from 2000 to 5000 allowing to resolve the [O II] doublet of faint emission line galaxies. The goal of the DESI survey is to acquire the spectra and measure the redshifts of 35 million galaxies and quasars. We present here an overview of the spectroscopic pipeline and its performances, in terms of wavelength and spectrophotometric calibration, sky background subtraction, redshift completeness and purity.