All Figures

$\begin{figure} \par\includegraphics[height=7.2cm,width=17.35cm,clip]{1827fig1.ps}\end{figure}$ Figure 1: Combined absorption-line spectra of Fe II associated with the $z_{\rm abs}$ = 1.839 damped Ly- $\alpha$ system toward Q 1101-264 (normalized intensities are shown by dots with 1 $\sigma$ error bars). The zero radial velocity is fixed at $z_{\rm abs}$ = 1.83888. Smooth lines are the synthetic Voigt profiles convolved with the point-spread spectrograph function. The mean signal-to-noise ratio per pixel at the continuum level is indicated in each panel. The normalized $\chi ^2_{\rm min} = 3.995$ (the number of degrees of freedom $\nu = 272$ ) shows that the Fe II profiles obtained in the framework of the standard data reduction procedure are not self-consistent.
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In the text

$\begin{figure} \par\includegraphics[height=14.5cm,width=7.6cm,clip]{1827fig2.ps}\end{figure}$ Figure 2: Emission line profiles from the thorium-argon calibration lamp. The lines are placed close to the centers of the UVES echelle orders of different settings which are indicated at the top left hand corners in the panels. The wavelength step size corresponds to the original pixel width. The numbering of the histograms are in accord with the list in Table 1. The 11th and 12th exposures are taken as reference. Note the difference between the relative shifts 5-11 and 6-12, while 21-11 and 22-12 show identical velocity offsets.
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In the text

$\begin{figure} \par\includegraphics[height=15cm,width=15cm,clip]{1827fig3.ps}\end{figure}$ Figure 3: Unnormalized portions of the Q 1101-264 spectra with the Fe II lines ( $z_{\rm abs}$ = 1.839) selected for the $\Delta \alpha /\alpha$ measurement. All lines are located near the centers of the UVES echelle orders. The corresponding settings are indicated at the bottom left hand corners in each panel. Dots with error bars are the mean intensities and their 1 $\sigma$ uncertainties - the values used to estimate the local continuum level by means of the linear regression analysis. For the selected Fe II lines, the continuum level is known with an accuracy better than 1%.
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In the text

$\begin{figure} \par\includegraphics[height=17.3cm,width=17.5cm,clip]{1827fig4.ps}\end{figure}$ Figure 4: Individual exposures of the Fe II lines in the spectrum of Q 1101-264 (normalized intensities are shown by dots with 1 $\sigma$ error bars) and over-potted synthetic profiles (smooth curves) calculated from the joint analysis. The minimization procedure gives $\chi ^2_{\rm min} = 1.097$ per degree of freedom (the number of data points m = 973, the number of fitting parameters p = 39). Dashed vertical lines mark positions of the individual components. The mean signal-to-noise ratio per pixel at the continuum level is indicated in each panel. Columns from the left to the right correspond to the exposures No. 11/12, 19/20, 21/22, and 23/24, in accord with Table 1. Spectral data shown in these columns are centered relative to the following fixed redshifts ( from the left to the right): 1.8389040, 1.8389041, 1.8389065, and 1.8389009.
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In the text

$\begin{figure} \par\includegraphics[height=13.9cm,width=8cm,clip]{1827fig5.ps}\end{figure}$ Figure 5: Upper panel: the residuals $\epsilon = ({\cal F}^{\rm cal} - {\cal F}^{\rm obs})$ for all Fe II profiles from Fig. 4. Dashed vertical lines indicate the positions of the subcomponents. Lower panel: shown are the distribution of $\epsilon$ (histogram) and the overplotted normal distribution (smooth curve) with the sample mean $\langle \epsilon \rangle = 3.5$ $\times$ 10^-4 and the dispersion $\sigma _\epsilon = 2.9$ $\times$ 10^-2 estimated from the total data set except for two "hot pixels'' with $\epsilon < -0.1$ (seen in the inset).
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In the text

$\begin{figure} \par\includegraphics[height=8.35cm,width=8cm,clip]{1827fig6.ps}\end{figure}$ Figure 6: The distribution of $\Delta \alpha /\alpha$ (histogram) from the $z_{\rm abs}$ = 1.839 and $z_{\rm abs}$ = 1.15 Fe II systems toward Q 1101-264 and HE 0515-4414, respectively. The distributions of $\Delta \alpha /\alpha$ from MFWDPW (dashed curve) and CSPA (dotted curve) are overplotted to demonstrate the discrepancy between the Keck/HIRES and VLT/UVES sample mean $\langle$ $\Delta \alpha /\alpha$ $\rangle$ values. Both MFWDPW and CSPA distributions are assumed to be normal with the means and variances taken from the corresponding papers. The vertical lines mark the centers of the distributions. The revealed Keck-VLT discrepancy of $\langle$ $\Delta \alpha /\alpha$ $\rangle$ is statistically significant at the 95% confidence level according to the t-test.
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In the text