The magnetic fields of white dwarfs

A full list of white dwarfs which have been observed for evidence of magnetic field is presented. The observations of continuous circular polarization are discussed along with the derivation of the mean field projected on the line of sight. New field upper limits are presented for several white dwarfs with strong spectral lines observed for the Zeeman effect. The obtained material is used to determine quantitatively the distribution of magnetic fields over the population of white dwarfs. The temperature, composition, and rotation of magnetic white dwarfs are examined, and the possible effect of white dwarf magnetic fields on accretion of material from the interstellar medium is considered. The space density and possible origin of magnetic white dwarfs is also discussed.