White Dwarf Classification of DESI DR1 Spectra1

We present a new catalog of spectroscopically confirmed white dwarfs from the Dark Energy Spectroscopic Instrument (DESI) Data Release 1. We visually classified 44,417 white dwarf spectra and derived atmospheric parameters for 29,072 DA white dwarfs through spectroscopic model fitting. The resulting mass distribution is non-Gaussian, with a mean mass of 0.677,M, consistent with previous studies. We identify 547 magnetic white dwarfs by detecting Zeeman splitting, including 84 new discoveries, and estimate their magnetic field strengths using off-centered, inclined dipole models when possible. We compare our magnetic field determinations with previous measurements and find overall good agreement. Finally, we investigate the relation between stellar properties and magnetism, finding that magnetic white dwarfs are systematically more massive than the general white dwarf population and that intermediate-strength magnetic fields are already present in stars that have not yet entered the crystallization phase. This result suggests that crystallization is unlikely to be the sole mechanism responsible for the origin of magnetic fields in white dwarfs.