Magnetic White Dwarfs from the SDSS. II. The Second and Third Data Releases

Fifty-two magnetic white dwarfs have been identified in spectroscopic observations from the Sloan Digital Sky Survey (SDSS) obtained between mid-2002 and the end of 2004, including Data Releases 2 and 3. Although not as numerous or diverse as the discoveries from the first data release, the collection exhibits polar field strengths ranging from 1.5 to ∼1000 MG and includes two new unusual atomic DQA examples, a molecular DQ, and five stars that show hydrogen in fields above 500 MG. The highest field example, SDSS J2346+3853, may be the most strongly magnetic white dwarf yet discovered. Analysis of the photometric data indicates that the magnetic sample spans the same temperature range as for nonmagnetic white dwarfs from the SDSS, and support is found for previous claims that magnetic white dwarfs tend to have larger masses than their nonmagnetic counterparts. A glaring exception to this trend is the apparently low-gravity object SDSS J0933+1022, which may have a history involving a close binary companion.