All Figures

$\begin{figure} \par\resizebox{8.5cm}{!}{\includegraphics[clip]{2488fig1.eps}}\par\end{figure}$ Figure 1: Total intensity image of the H₂O maser features around U Her. The inlay shows the total intensity spectrum of the U Her H₂O masers, where the solid vertical line indicates the stellar velocity and the dashed vertical line indicates the velocity of the maser feature that was found to be coincident with stellar position in Vlemmings et al. (2002).
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In the text

$\begin{figure} \resizebox{17cm}{!}{\includegraphics[clip]{2488fig2.eps}}\end{figure}$ Figure 2: ( left) Total intensity image of the H₂O maser features around U Ori. ( right) Total power (I) and V-spectra for selected maser features of U Ori. The bottom panel shows the best fitting synthetic V-spectrum produced by the standard LTE Zeeman interpretation (dashed line). The middle panel shows the best non-LTE model fit (dotted line). The corresponding total power fits are shown in the top panel. The V-spectra in the lower two panels are adjusted by removing a scaled down version of the total power spectrum as indicated in Sect. 3, which is different for the LTE and non-LTE fits. The solid vertical lines show the expected position of the minimum and maximum of the V-spectrum in the general LTE interpretation.
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In the text

$\begin{figure} \par\resizebox{17.5cm}{!}{\includegraphics[clip]{2488fig3.eps}}\end{figure}$ Figure 3: Similar to Fig. 2 for VX Sgr.
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In the text

$\begin{figure} \par\resizebox{17.5cm}{!}{\includegraphics[clip]{2488fig4.eps}}\end{figure}$ Figure 4: Similar to the spectra in Figs. 2 and 3 for additional maser features around VX Sgr. Feature VX Sgr n suffers from some interference effect in the right wing of the spectrum but this does not affect the magnetic field determination.
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In the text

$\begin{figure} \par\resizebox{18cm}{!}{\includegraphics[clip]{2488fig5.eps}}\hfill \end{figure}$ Figure 5: The best fitted dipole magnetic field for the H₂O maser observations around VX Sgr (denoted by the solid circle). ( left) The distribution of the H₂O maser features indicating the measured magnetic field strengths. Open symbols denote a positive magnetic field while the closed symbols correspond to a negative magnetic field. The crosses represent the upper limits. The symbols have been scaled relative to the magnetic field strength. ( right) The distribution of the H₂O maser features indicating the velocity structure of the maser features. The open symbols are the red-shifted features and the solid symbols are the blue-shifted features. The size indicates the velocity difference with the stellar velocity ( $v_{\rm rad} = 5.3$ km s^-1)
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In the text

$\begin{figure} \par\resizebox{8.5cm}{!}{\includegraphics[clip]{2488fig6.ps}}\hfill \end{figure}$ Figure 6: Magnetic field strength, B, as function of distance, R, from the center of the star. Dashed-dotted boxes are the estimates for the magnetic fields in the OH and SiO maser regions of Mira stars, solid boxes are those for the supergiants. The dashed-dotted line indicates a solar-type magnetic field and the dotted line indicates the dipole field. The solid symbols are the previously observed stars (U Her: triangles; S Per: squares; VY CMa: crosses and NML Cyg: hexagonals). The open symbols indicate the stars of the sample presented here (U Her: triangle; VX Sgr: hexagonal and U Ori: circle). Note that the open triangle only indicates the upper limit determined for the most recent observation of U Her. Also note that the magnetic field strength observed on the OH masers of U Ori is larger than the typically observed fields for Mira variables. The dashed lines represent estimates of the stellar radius.
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In the text

$\begin{figure} \par\resizebox{8.5cm}{!}{\includegraphics[clip]{2488fig1.eps}}\par\end{figure}$	Figure 1: Total intensity image of the H₂O maser features around U Her. The inlay shows the total intensity spectrum of the U Her H₂O masers, where the solid vertical line indicates the stellar velocity and the dashed vertical line indicates the velocity of the maser feature that was found to be coincident with stellar position in Vlemmings et al. (2002).
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$\begin{figure} \par\resizebox{17.5cm}{!}{\includegraphics[clip]{2488fig3.eps}}\end{figure}$	Figure 3: Similar to Fig. 2 for VX Sgr.
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$\begin{figure} \par\resizebox{17.5cm}{!}{\includegraphics[clip]{2488fig4.eps}}\end{figure}$	Figure 4: Similar to the spectra in Figs. 2 and 3 for additional maser features around VX Sgr. Feature VX Sgr n suffers from some interference effect in the right wing of the spectrum but this does not affect the magnetic field determination.
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