All Figures

$\begin{figure} \par\resizebox{11.7cm}{!}{\includegraphics[clip]{aa3245f1.eps}} \hspace*{4mm} \parbox[b]{50mm}{} \end{figure}$ Figure 1: Comparison of theoretical colors, B-V vs. U-B, for two grids of pure hydrogen, hot DA atmospheres. Models are computed either with the TLUSTY195 and SYNSPEC42 NLTE codes, or with our ATM21 code based on the nonideal EOS and Los Alamos opacities. Consistency of both families of broadband B-V and U-B indices is not perfect but is satisfactory.
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In the text

$\begin{figure} \par\resizebox{8.8cm}{!}{{\includegraphics[clip]{aa3245f2.eps}}} \end{figure}$ Figure 2: Pure iron and hydrogen LTE white dwarf synthetic spectra of $T_{\rm eff}= 20~000$ K and $\log g =8.0$ , displayed on wide range of wavelengths from near infrared, $\lambda = 10~000$ Å, down to about 500 Å. Solid line represents the spectrum of pure iron model and dotted line is the spectrum of pure H atmosphere. Both model spectra are computed using the EOS of nonideal gas and the Los Alamos TOPS monochromatic opacities.
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In the text

$\begin{figure} \par\resizebox{8.8cm}{!}{{\includegraphics[clip]{aa3245f3.eps}}} \end{figure}$ Figure 3: The LTE theoretical spectra of iron and hydrogen atmospheres of Fig. 1 are displayed here on narrower range of wavelengths, with higher resolution, from near $\lambda = 3200$ Å up to 8000 Å. The solid line represents the spectrum of a pure iron model and the dotted line is the spectrum of a pure H atmosphere.
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In the text

$\begin{figure} \par\resizebox{8.8cm}{!}{{\includegraphics[clip]{aa3245f4.eps}}} \end{figure}$ Figure 4: Same as Fig. 2 for $T_{\rm eff}= 30~000$ K and $\log g =8.0$ .
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In the text

$\begin{figure} \par\resizebox{8.8cm}{!}{{\includegraphics[clip]{aa3245f5.eps}}} \end{figure}$ Figure 5: Same as Fig. 2 for $T_{\rm eff}= 50~000$ K and $\log g = 9.0$ . Note that the surface gravity is higher than in previous figures.
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In the text

$\begin{figure} \par\resizebox{8.8cm}{!}{{\includegraphics[clip]{aa3245f6.eps}}} \par\end{figure}$ Figure 6: Same as Fig. 2 for $T_{\rm eff}= 70~000$ K and $\log g = 9.0$ .
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In the text

$\begin{figure} \par\resizebox{8.8cm}{!}{{\includegraphics[clip]{aa3245f7.eps}}} \end{figure}$ Figure 7: Same as Fig. 2 for $T_{\rm eff}=100~000$ K and $\log g = 9.0$ .
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In the text

$\begin{figure} \par\includegraphics[clip]{aa3245f8.eps} \end{figure}$ Figure 8: Plot of U-B vs. B-V for hot white dwarf stars. The shaded area denotes the region occupied by colors of pure iron model atmospheres computed in this paper. Numbers put in this area denote effective temperatures $T_{\rm eff}$ (in thousands K) and $\log g$ , respectively. Colors of pure hydrogen models (nonideal EOS) are represented by the transparent grid of sections. Asterisks denote colors of real white dwarfs, as taken from McCook & Sion (1999). One can see that only few real white dwarfs fall into the shaded area.
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In the text

$\begin{figure} \par\includegraphics[clip]{aa3245f9.eps} \end{figure}$ Figure 9: Plot of B-V vs. V-I for hot white dwarf stars. Also here, shaded area and the adjacent numbers correspond to the colors of pure Fe model atmospheres. The transparent grid of sections corresponds to pure H models (nonideal EOS). Unfortunately, there are no observed color indices available.
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In the text

$\begin{figure} \par\includegraphics[clip]{aa3245f10.eps} \end{figure}$ Figure 10: Plot of U-B vs. B-V for hot stratified Fe/H model atmospheres. In these models, pure Fe atmosphere is covered by a pure H layer, reaching from the standard optical depth $\tau = 10^{-10}$ down to 10^-3 in all cases. Designations of $T_{\rm eff}$ and $\log g$ have the same meaning as in previous figures. Pure H models are also represented in the same way.
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In the text

$\begin{figure} \par\includegraphics[clip]{aa3245f11.eps} \end{figure}$ Figure 11: Plot of B-V vs. V-I for Fe/H stratified atmospheres. Again, no observations of real white dwarfs are available here.
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In the text

$\begin{figure} \par\resizebox{8.8cm}{!}{{\includegraphics[clip]{aa3245f12.eps}}} \end{figure}$ Figure 12: Catalog of $M/M_{\odot }$ vs. $\log g$ determinations for two sets of DA white dwarfs. Dots denote stars observed by EUVE satellite by Finley et al. (1997). Crosses represent data from the Hamburg Quasar Survey (Homeier et al. 1998). All the investigated stars are located in a well defined strip corresponding to C-O white dwarf cores. No single star with too high $\log g$ is seen in the figure.
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In the text

$\begin{figure} \par\resizebox{11.7cm}{!}{\includegraphics[clip]{aa3245f1.eps}} \hspace*{4mm} \parbox[b]{50mm}{} \end{figure}$	Figure 1: Comparison of theoretical colors, B-V vs. U-B, for two grids of pure hydrogen, hot DA atmospheres. Models are computed either with the TLUSTY195 and SYNSPEC42 NLTE codes, or with our ATM21 code based on the nonideal EOS and Los Alamos opacities. Consistency of both families of broadband B-V and U-B indices is not perfect but is satisfactory.
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$\begin{figure} \par\resizebox{8.8cm}{!}{{\includegraphics[clip]{aa3245f3.eps}}} \end{figure}$	Figure 3: The LTE theoretical spectra of iron and hydrogen atmospheres of Fig. 1 are displayed here on narrower range of wavelengths, with higher resolution, from near $\lambda = 3200$ Å up to 8000 Å. The solid line represents the spectrum of a pure iron model and the dotted line is the spectrum of a pure H atmosphere.
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$\begin{figure} \par\resizebox{8.8cm}{!}{{\includegraphics[clip]{aa3245f4.eps}}} \end{figure}$	Figure 4: Same as Fig. 2 for $T_{\rm eff}= 30~000$ K and $\log g =8.0$ .
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$\begin{figure} \par\resizebox{8.8cm}{!}{{\includegraphics[clip]{aa3245f5.eps}}} \end{figure}$	Figure 5: Same as Fig. 2 for $T_{\rm eff}= 50~000$ K and $\log g = 9.0$ . Note that the surface gravity is higher than in previous figures.
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$\begin{figure} \par\resizebox{8.8cm}{!}{{\includegraphics[clip]{aa3245f6.eps}}} \par\end{figure}$	Figure 6: Same as Fig. 2 for $T_{\rm eff}= 70~000$ K and $\log g = 9.0$ .
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$\begin{figure} \par\resizebox{8.8cm}{!}{{\includegraphics[clip]{aa3245f7.eps}}} \end{figure}$	Figure 7: Same as Fig. 2 for $T_{\rm eff}=100~000$ K and $\log g = 9.0$ .
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$\begin{figure} \par\includegraphics[clip]{aa3245f9.eps} \end{figure}$	Figure 9: Plot of B-V vs. V-I for hot white dwarf stars. Also here, shaded area and the adjacent numbers correspond to the colors of pure Fe model atmospheres. The transparent grid of sections corresponds to pure H models (nonideal EOS). Unfortunately, there are no observed color indices available.
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$\begin{figure} \par\includegraphics[clip]{aa3245f10.eps} \end{figure}$	Figure 10: Plot of U-B vs. B-V for hot stratified Fe/H model atmospheres. In these models, pure Fe atmosphere is covered by a pure H layer, reaching from the standard optical depth $\tau = 10^{-10}$ down to 10^-3 in all cases. Designations of $T_{\rm eff}$ and $\log g$ have the same meaning as in previous figures. Pure H models are also represented in the same way.
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$\begin{figure} \par\includegraphics[clip]{aa3245f11.eps} \end{figure}$	Figure 11: Plot of B-V vs. V-I for Fe/H stratified atmospheres. Again, no observations of real white dwarfs are available here.
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