All Figures

$\begin{figure} \par\includegraphics[width=7cm]{4635fig1.eps}\end{figure}$ Figure 1: Ultraviolet C IV line profile variability of $\nu$ Eri. The normalised flux in the upper panel is given in units of 10^-9 erg cm^-2 s^-1 Å^-1. The lower panel display the ratio of the observed variance to the expected variance ( $\sigma _{{\rm obs}}/\sigma _{{\rm exp}}$ ). The significant variations at red shifted wavelengths (around $\sim$ 100 km s^-1) are similar to those observed in other magnetic B stars, including the He strong and He weak stars. The spectra of $\nu$ Eri were corrected for the calculated radial velocity shift due to the pulsations.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=7.5cm,clip]{4635fig2.eps}\end{figure}$ Figure 2: UV continuum flux near C IV measured with IUE (dots - typical errors are 0.002) and the normalised U-band flux (line) deduced from the photometric pulsation analysis in Papers I and III; the typical error range is indicated by the dashed lines. The timescales of the variability observed in the UV and in the U-band are very similar.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[angle=-90,width=7cm,clip]{4635fig3.ps}\end{figure}$ Figure 3: LSD results for $\nu$ Eri on 8 Feb. 2003. The average intensity line profile ( bottom), the Stokes V profile ( middle) and the Stokes N profile ( top) are shown. V and N are shifted up by 1.05 and 1.10 respectively for display purposes. Note the signature in V which is typical for a magnetic field, but the presence of a signature in N, generated by the pulsations, indicates that the Stokes V profile could be affected (see text).
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=18cm]{4635f4.eps}\end{figure}$ Figure 4: Stokes I, N and V profiles of observations 1 ( left), 2 ( middle) and 6 ( right). These profiles were selected to illustrate the effect of the pulsation. In the Stokes I plots ( top), the solid lines represent the model fits. The dashed lines are the four exposures that were used for one magnetic field measurement. In the plots of the Stokes N ( middle) and V ( bottom, in ), the dashed line represents the observations, the thin solid line the model, and the thick solid line the corrected observations after subtracting the model to correct for the effect of the pulsations. Note that the corrected Stokes N profiles are all consistent with zero, which indicates that the assumption of a constant velocity shift between the two beams is sufficient to explain the signatures in Stokes N for pulsation-affected profiles. The limits of [-0.04%, +0.04%] adopted in Sect. 3.3 as the maximum amplitude of any undetected, broad, magnetic polarisation signatures, are indicated by the dashed lines in the bottom left plot.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=6.2cm,clip]{4635fig5.eps}\end{figure}$ Figure 5: For a given magnetic field strength, the amplitude of the Stokes V signature depends mainly on $\alpha$ , the angle between the rotation axis projected onto the plane of the sky and the magnetic axis.
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[angle=-90,width=5.2cm,clip]{4635fig6a.ps}\hs... ...ace*{2mm} \includegraphics[angle=-90,width=5.2cm,clip]{4635fig6c.ps}\end{figure}$ Figure 6: Results of model calculations of Stokes V profiles for a star with a dipolar magnetic field with a polar strength of 300 G. The left plot shows profiles for an inclination of $i=0^\circ$ , an angle between the rotation and magnetic axis of $\beta =90^\circ$ and for rotation angle $\phi =0^\circ$ (magnetic axis pointing towards observer, maximum $B_{{\rm eff}}$ - solid line), $\phi =30^\circ$ (dashed line), $\phi =60^\circ$ (dashed-dotted line) and $\phi =90^\circ$ (zero $B_{{\rm eff}}$ - dotted line). Although the shape of the signature and $B_{{\rm eff}}$ vary, the maximum amplitude remains approximately constant. The middle plot shows the profiles for $i=0^\circ$ , $\phi =90^\circ$ and $\beta =0^\circ$ (solid line), $\beta =30^\circ$ (dashed line), $\beta =60^\circ$ (dashed-dotted line) and $\beta =90^\circ$ (dotted line). On the right we show the maximum amplitude of the Stokes V profile vs. $\alpha$ for $\phi =90^\circ$ (squares), $\phi =45^\circ$ (triangles) and $\phi =0^\circ$ (circles). The lines represent $\sin(\alpha)$ normalised to $\alpha =90^\circ$ (with $i=0^\circ$ , $\beta =\alpha$ ). The maximum amplitude roughly scales with $\sin(\alpha)$ with a slight dependency on the orientation (as can also be seen in the left plot).
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[angle=-90,width=6.8cm,clip]{4635fig7.ps}\end{figure}$ Figure 7: Upper limit to the magnetic field strength at the magnetic pole as a function of the angle $\alpha$ .
Open with DEXTER

In the text

$\begin{figure} \par\includegraphics[width=7.5cm,clip]{4635fig2.eps}\end{figure}$	Figure 2: UV continuum flux near C IV measured with IUE (dots - typical errors are 0.002) and the normalised U-band flux (line) deduced from the photometric pulsation analysis in Papers I and III; the typical error range is indicated by the dashed lines. The timescales of the variability observed in the UV and in the U-band are very similar.
Open with DEXTER

$\begin{figure} \par\includegraphics[width=6.2cm,clip]{4635fig5.eps}\end{figure}$	Figure 5: For a given magnetic field strength, the amplitude of the Stokes V signature depends mainly on $\alpha$ , the angle between the rotation axis projected onto the plane of the sky and the magnetic axis.
Open with DEXTER

$\begin{figure} \par\includegraphics[angle=-90,width=6.8cm,clip]{4635fig7.ps}\end{figure}$	Figure 7: Upper limit to the magnetic field strength at the magnetic pole as a function of the angle $\alpha$ .
Open with DEXTER