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Count rate predictions for model atmosphere spectra


The model atmospheres (the atmospheres were computed by M.A.Barstow using computer code originally developed by G.A.Williams, J.Brooker and A.R.King) used here are:

Models (i) and (ii) are representative models for hot DA white dwarfs ( tex2html_wrap_inline3156  K) with different compositions. Care should always be taken when interpreting the results given in Figures 12.6 gif and 12.7gif since XUV fluxes are extremely sensitive to He abundances which can differ markedly from these models in individual objects.

For each model atmosphere, and for each of the scientific filters as listed in Table 5.3 gif, Figures 12.6 gif and 12.7gif show the expected WFC count rate as a function of temperature for a set of column densities tex2html_wrap_inline2416 varying from tex2html_wrap_inline2430 to tex2html_wrap_inline2656  cm tex2html_wrap_inline1930 . For these model atmospheres the plots are normalized to a V-magnitude tex2html_wrap_inline3166 , thus the estimated WFC count rate can be determined simply by scaling the conversion factor (CF) to the V-magnitude of the source in question, tex2html_wrap_inline3168 , i.e., tex2html_wrap_inline3170 .

Michael Arida
Tue Jun 11 16:18:41 EDT 1996