AAS 201st Meeting, January, 2003
Session 119. White Dwarfs
Poster, Thursday, January 9, 2003, 9:20am-4:00pm, Exhibit Hall AB

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[119.10] Hard X-ray Emission from White Dwarfs

Y.-H. Chu, C.J. Dodd, K. Gillani, R.A. Gruendl, M.A. Guerrero, A.L. Maxham, I.J. O'Dwyer, R.F. Webbink (UIUC)

White dwarfs can be soft X-ray (<0.4 keV) sources if their temperatures are high and atmospheric opacities are low. Hard X-ray emission (~1 keV) associated with white dwarfs has been attributed to either a late-type companion with coronal activity or accretion of stellar material from a companion onto the surface of a white dwarf. However, using the ROSAT archive we have found hard X-ray emission from a number of apparently single white dwarfs. The most intriguing case is WD\,1134+300 (GD\,140), whose PSPC spectrum shows distinct hard X-ray emission, but whose 2MASS photometry shows no near-IR excess. Its small distance, 15 pc, helps to rule out the possibility of a hidden stellar-mass companion. New hard X-ray mechanisms are needed for white dwarfs. We are undertaking a thorough search for hard X-ray emission from white dwarfs using the entire ROSAT archive. We will produce a complete catalog of X-ray sources associated with white dwarfs and provide X-ray spectral information.

The author(s) of this abstract have provided an email address for comments about the abstract: chu@astro.uiuc.edu

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