All Figures

$\begin{figure} \par\includegraphics[width=8.3cm,clip]{f_1437_01.ps} \end{figure}$ Figure 1: H $\alpha$ line profile fit for WD 0251-008. The observed profile is compared to non-rotating synthetic line profiles calculated at 14 400 K as derived from photometry (dashed line) and 7700 K as we found from the H $_\alpha$ line fit (solid line).
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=12.55cm,clip]{f_1437_02.ps}\... ...*{2mm} \includegraphics[angle=-90,width=12.55cm,clip]{f_1437_09.ps} \end{figure}$ Figure 2: H $\alpha$ line profile fits and upper limits for the projected rotational velocities of four DA stars. For each star the upper panel displays the run of $\Delta \chi ^2$ with $v \sin i$ from which the upper limits were read off, the lower panel displays the match of the observed profile by a line profile without rotation (dashed line) and for the maximum $v \sin i$ deduced from the 3 $\sigma$ limit (full line).
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=12.8cm,clip]{f_1437_03.ps}\v... ...e*{3mm} \includegraphics[angle=-90,width=12.8cm,clip]{f_1437_10.ps} \end{figure}$ Figure 3: H $\alpha$ line profile fits and best fits for the projected rotational velocities of four DA stars. For each star the upper panel displays the run of $\Delta \chi ^2$ with $v \sin i$ from which the best fit projected rotational velocity is read off, the lower panel displays the match of the observed profile by a line profile without rotation (dashed line) and for the best fit $v \sin i$ (full line).
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In the text

$\begin{figure} \par\includegraphics[width=8.3cm,clip]{f_1437_04.ps} \end{figure}$ Figure 4: H $\alpha$ line profile fits for the ZZ Ceti variable WD 0921+354 (G117-B15A). The upper panel displays the run of $\Delta \chi ^2$ with $v \sin i$ from which the best fit and error limits are read off, the lower panel displays the match of the observed profile by a line profile without rotation (dashed line) and for the best fit $v \sin i$ (full line).
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In the text

$\begin{figure} \par\includegraphics[width=8.5cm,clip]{f_1437_05.ps} \end{figure}$ Figure 5: H $\alpha$ line profile fits for the ZZ Ceti variable WD 0921+354 ( middle) compared to those of the rotating star WD 1706+354 ( top) and the non-rotating star WD 1716+020 ( bottom). The line core of G117-B15A cannot be matched by a rotational profile.
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In the text

$\begin{figure} \par\includegraphics[width=8.3cm,clip]{f_1437_06.ps} \end{figure}$ Figure 6: H $\alpha$ line profile fit for WD 0628-020, a star with a peculiar H $\alpha$ line profile. The upper panel displays the run of $\Delta \chi ^2$ with $v \sin i$ from which the best fit and error limits are read off. The lower panel compares the observed profile to a synthetic line profile calculated without rotation (dashed line) and for the best fit $v \sin i$ (full line). Obviously the observed line profile is not matched by either profiles. While the line core is well matched assuming no rotation at all, the inner wings cannot be matched by any reasonable rotation velocity.
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In the text

$\begin{figure} \par\includegraphics[width=8.3cm,clip]{f_1437_07.ps} \end{figure}$ Figure 7: H $\alpha$ line profile fit for WD 0628-020. The observed profile is compared to a synthetic line profile calculated at a temperature 1000 K below the value given in Table 1 and for $v \sin i = 20$ km s^-1. While the line core and the inner line wings are matched perfectly, the outer line wings are not reproduced very well.
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In the text

$\begin{figure} \par\includegraphics[width=8.3cm,clip]{f_1437_08.ps} \end{figure}$ Figure 8: $T_{\rm eff}-\log g$ diagram for DA white dwarfs from Papers I and II and this paper. Stars are marked as open triangles if the rotation velocity derived from our analysis exceeds a 20 km s^-1 limit within the error margins. Non-rotating objects or "slow'' rotators are indicated as filled triangles, while open squares marked objects with peculiar line broadening due to magnetic fields. ZZ Ceti stars are displayed as open circles. Also shown are evolutionary tracks for white dwarfs (Blöcker 1995, solid lines; and Driebe et al. 1998, dashed lines) labelled with the stellar masses.
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In the text

$\begin{figure} \par\includegraphics[width=8.3cm,clip]{f_1437_01.ps} \end{figure}$	Figure 1: H $\alpha$ line profile fit for WD 0251-008. The observed profile is compared to non-rotating synthetic line profiles calculated at 14 400 K as derived from photometry (dashed line) and 7700 K as we found from the H $_\alpha$ line fit (solid line).
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$\begin{figure} \par\includegraphics[width=8.3cm,clip]{f_1437_04.ps} \end{figure}$	Figure 4: H $\alpha$ line profile fits for the ZZ Ceti variable WD 0921+354 (G117-B15A). The upper panel displays the run of $\Delta \chi ^2$ with $v \sin i$ from which the best fit and error limits are read off, the lower panel displays the match of the observed profile by a line profile without rotation (dashed line) and for the best fit $v \sin i$ (full line).
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$\begin{figure} \par\includegraphics[width=8.5cm,clip]{f_1437_05.ps} \end{figure}$	Figure 5: H $\alpha$ line profile fits for the ZZ Ceti variable WD 0921+354 ( middle) compared to those of the rotating star WD 1706+354 ( top) and the non-rotating star WD 1716+020 ( bottom). The line core of G117-B15A cannot be matched by a rotational profile.
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$\begin{figure} \par\includegraphics[width=8.3cm,clip]{f_1437_07.ps} \end{figure}$	Figure 7: H $\alpha$ line profile fit for WD 0628-020. The observed profile is compared to a synthetic line profile calculated at a temperature 1000 K below the value given in Table 1 and for $v \sin i = 20$ km s^-1. While the line core and the inner line wings are matched perfectly, the outer line wings are not reproduced very well.
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