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J. Heise, J.S. Kaastra, F. Paerels, H.W. Hartmann, R.L.J. van der Meer, A.C. Brinkman (Space Research Organization Netherlands)
High resolution X-ray spectra of the hot white dwarfs.
Hot white dwarfs have been observed with Chandra LETG and XMM-Newton RGS as part of the inflight calibration. The DA white dwarfs Sirius B and HZ43 have been observed with the Low Energy Transmission Gratings on Chandra, while the supersoft source CAL 83 was observed with the Reflection Grating Spectrometer on XMM-Newton. The X-ray emission in these objects are thought to be the high energy tail of the (optically thick) emission of a hot high gravity atmosphere. The observed slope of the X-ray continuum of hot white dwarfs is extremely sensitive to model parameters of the atmosphere: effective temperature, gravity and element abundances. We will discuss how well the continuum and absorption features can be described by model atmospheres and how the model parameters are limited by the accuracy of the calibration.
The author(s) of this abstract have provided an email address for comments about the abstract: j.heise@sron.nl