AAS 205th Meeting, 9-13 January 2005
Session 103 White Dwarfs
Poster, Wednesday, January 12, 2005, 9:20am-6:30pm, Exhibit Hall

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[103.05] The Search for Magnetic White Dwarfs in Pre-Cataclysmic Binaries from the SDSS

M. P. Lemagie, N. M. Silvestri, S. L. Hawley (U. Washington), G. D. Schmidt, J. Liebert (Steward Observatory; U. Arizona), M. A. Wolfe (U. Washington)

We present the results of our investigation of white dwarfs in several hundred close binary systems from the SDSS. The close binary systems in this study are believed to be the progenitors of cataclysmic variables. Since approximately 25% of the known cataclysmic variables have magnetic white dwarfs, many of the white dwarfs in our large sample of pre-cataclysmic binary systems should have a measurable magnetic field. A cursory inspection of the composite spectra of these systems however, reveals no obvious magnetic white dwarfs, possibly because of the low signal-to-noise of the spectrum and/or the contamination of the white dwarf spectrum by the low mass companion. To reduce the contamination, we first subtract the low mass companion from the composite SDSS spectrum. We then smooth and compare the Balmer absorption features of the remaining DA white dwarf spectrum to magnetic models at a variety of field strengths. Our search reveals only about 10 magnetic white dwarf stars in these systems. All of the candidate magnetic white dwarfs have relatively low magnetic field strengths (< 10 MG), as expected. Our techniques for finding magnetic white dwarfs in these systems, their physical properties, and the implications of our results are discussed.

This work was supported in part by NSF Grant AST02-05875.

The author(s) of this abstract have provided an email address for comments about the abstract: mlemagie@u.washington.edu

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