Astronomy & Astrophysics

All Figures

$\begin{figure} \par\includegraphics[width=7.5cm,clip]{0562f01.eps} \end{figure}$ Figure 1: Overview of the VINCI data analysis work flow. The shaded area delimits the processing executed automatically by the instrument data pipeline. The hatched area (lower right) covers the astrophysical interpretation of the measured visibility, not adressed in the present paper.
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In the text

$\begin{figure} \par\includegraphics[width=8.4cm,clip]{0562f02.eps} \end{figure}$ Figure 2: View of the VINCI instrument installed in the VLTI interferometric laboratory. The MONA beam combiner is the visible above the center of the image (white box), with its optical fiber inputs and outputs. The beams coming from the VLTI Delay Lines enter the optical table from the bottom of the picture.
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In the text

$\begin{figure} \par\includegraphics[width=8.2cm,clip]{0562f03.eps} \end{figure}$ Figure 3: Principle of the VINCI instrument.
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In the text

$\begin{figure} \par\includegraphics[width=8.5cm,clip]{0562f04.eps} \end{figure}$ Figure 4: Principle of the MONA beam combiner.
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In the text

$\begin{figure} \par\includegraphics[width=15.7cm,clip]{0562f05.eps} \end{figure}$ Figure 5: The raw signals I₁, I₂, $P_{\rm A}$ and $P_{\rm B}$ , for one interferogram obtained on $\theta$ Cen. The original signals have been translated vertically respectively by +90, +40, +40 and 0 ADUs for clarity.
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In the text

$\begin{figure} \par\includegraphics[width=7.8cm,clip]{0562f06.eps} \end{figure}$ Figure 6: Photometric calibration of the I₁ signal. The raw I₁ signal is the black line in the upper part of the plot, the photometric calibration signal $\kappa _{\rm 1A} P_{\rm A} - \kappa _{\rm 1B} P_{\rm B}$ is the superimposed grey line, and the result of the subtraction is the lower curve.
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In the text

$\begin{figure} \par\includegraphics[width=8cm,clip]{0562f07.eps} \end{figure}$ Figure 7: Average power spectral density of the $P_{\rm A}$ and $P_{\rm B}$ signals as measured on $\theta$ Cen. From top to botton: $\widetilde{P_{\rm A}}^2$ , noise model $\widetilde{N_{\rm A}}^2$ (upper dotted line), $\widetilde{P_{\rm B}}^2$ , noise model $\widetilde{N_{\rm B}}^2$ (lower dotted line).
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In the text

$\begin{figure} \par\includegraphics[width=7.8cm,clip]{0562f08.ps} \end{figure}$ Figure 8: Wiener filters computed from $\theta$ Cen photometric signals (Fig. 7). $W_{\rm A}$ is the upper line, and $W_{\rm B}$ the lower line.
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In the text

$\begin{figure} \par\includegraphics[width=8cm,clip]{0562f09.eps} \end{figure}$ Figure 9: Photometric normalization signal P (thick line), with the Wiener filtered $P_{\rm A}$ (dashed line) and $P_{\rm B}$ channels (thin line). P is the geometric mean of the two filtered photometric channels.
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In the text

$\begin{figure} \par\includegraphics[width=8cm,clip]{0562f10.eps} \end{figure}$ Figure 10: From top to bottom: I₁ normalized interferogram (black), I₂ normalized interferogram (grey), and the result I of the subtraction of these two signals. For clarity, the I₁ and I₂ signals are shifted vertically by +2 and +1, respectively. The correlated noise has disappeared in the combined signal and the fringe packet appears more clearly.
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In the text

$\begin{figure} \par\includegraphics[width=8.5cm,clip]{0562f11.ps}\par\vspace*{2mm} \includegraphics[width=8.5cm,clip]{0562f12.ps} \end{figure}$ Figure 11: Wavelet power spectral densities of processed interferograms ( $\sigma$ represents the wave number, i.e. the inverse of the wavelength). The upper figure shows the WPSD of a good quality interferogram: the energy is well confied in the fringe power peak. The bottom WPSD is affected by strong atmospheric piston: a significant part of the fringe power is spread outside of the theoretical fringe peak, both in time and frequency domains. The isocontours delimit 77% and 76% of the total modulated power, respectively.
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In the text

$\begin{figure} \par\includegraphics[width=8.4cm,clip]{0562f13.eps}\par\vspace*{2mm} \includegraphics[width=8.4cm,clip]{0562f14.eps} \end{figure}$ Figure 12: Squared coherence factor $\mu ^2$ as a function of the photometric signal on the fringe packet, for the sample batches obtained on $\alpha$ Cen A ( top) and $\theta$ Cen ( bottom). The dashed lines show the mean value of the series derived using the bootstrap technique.
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In the text

$\begin{figure} \par\includegraphics[width=8cm,clip]{0562f15.eps} \end{figure}$ Figure 13: Average WPSD of the $\alpha$ Cen A observation. The original two-dimensional matrix has been integrated over the fringe packet length in the time domain. The resulting projection on the wave number axis allows one to visualize clearly the noise contribution. The subtracted noise model is shown by the dashed line. The final WPSD (thick line) shows no bias in spite of the large brightness of the star and very low squared coherence factor of the fringes ( $\mu ^2 \approx 0.3$ %).
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In the text

$\begin{figure} \par\includegraphics[width=8.1cm,clip]{0562f16.eps} \end{figure}$ Figure 14: Histogram of the $\mu ^2$ values obtained on $\theta$ Cen. No significant skewness is present.
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In the text

$\begin{figure} \par\includegraphics[width=8.1cm,clip]{0562f17.eps} \end{figure}$ Figure 15: Histogram of the $\mu ^2$ values obtained on $\alpha$ Cen A.
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In the text

$\begin{figure} \par\includegraphics[width=8cm,clip]{0562f18.eps} \end{figure}$ Figure 16: Evolution of the transfer function T² during one night (2002-05-29) on the E0-G0 baseline of the VLTI (16 m in ground length). Each symbol corresponds to a different star.
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In the text

$\begin{figure} \par\includegraphics[width=8cm,clip]{0562f19.eps}\end{figure}$ Figure A.1: VINCI interferometric fringes (upper curve, from a processed interferogram of $\theta$ Cen) and the Morlet wavelet function imaginary part (bottom curve).

In the text

$\begin{figure} \par\includegraphics[width=7.5cm,clip]{0562f01.eps} \end{figure}$	Figure 1: Overview of the VINCI data analysis work flow. The shaded area delimits the processing executed automatically by the instrument data pipeline. The hatched area (lower right) covers the astrophysical interpretation of the measured visibility, not adressed in the present paper.
Open with DEXTER

$\begin{figure} \par\includegraphics[width=8.4cm,clip]{0562f02.eps} \end{figure}$	Figure 2: View of the VINCI instrument installed in the VLTI interferometric laboratory. The MONA beam combiner is the visible above the center of the image (white box), with its optical fiber inputs and outputs. The beams coming from the VLTI Delay Lines enter the optical table from the bottom of the picture.
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$\begin{figure} \par\includegraphics[width=8.2cm,clip]{0562f03.eps} \end{figure}$	Figure 3: Principle of the VINCI instrument.
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$\begin{figure} \par\includegraphics[width=8.5cm,clip]{0562f04.eps} \end{figure}$	Figure 4: Principle of the MONA beam combiner.
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$\begin{figure} \par\includegraphics[width=15.7cm,clip]{0562f05.eps} \end{figure}$	Figure 5: The raw signals I₁, I₂, $P_{\rm A}$ and $P_{\rm B}$ , for one interferogram obtained on $\theta$ Cen. The original signals have been translated vertically respectively by +90, +40, +40 and 0 ADUs for clarity.
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$\begin{figure} \par\includegraphics[width=7.8cm,clip]{0562f06.eps} \end{figure}$	Figure 6: Photometric calibration of the I₁ signal. The raw I₁ signal is the black line in the upper part of the plot, the photometric calibration signal $\kappa _{\rm 1A} P_{\rm A} - \kappa _{\rm 1B} P_{\rm B}$ is the superimposed grey line, and the result of the subtraction is the lower curve.
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$\begin{figure} \par\includegraphics[width=8cm,clip]{0562f07.eps} \end{figure}$	Figure 7: Average power spectral density of the $P_{\rm A}$ and $P_{\rm B}$ signals as measured on $\theta$ Cen. From top to botton: $\widetilde{P_{\rm A}}^2$ , noise model $\widetilde{N_{\rm A}}^2$ (upper dotted line), $\widetilde{P_{\rm B}}^2$ , noise model $\widetilde{N_{\rm B}}^2$ (lower dotted line).
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$\begin{figure} \par\includegraphics[width=7.8cm,clip]{0562f08.ps} \end{figure}$	Figure 8: Wiener filters computed from $\theta$ Cen photometric signals (Fig. 7). $W_{\rm A}$ is the upper line, and $W_{\rm B}$ the lower line.
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$\begin{figure} \par\includegraphics[width=8cm,clip]{0562f09.eps} \end{figure}$	Figure 9: Photometric normalization signal P (thick line), with the Wiener filtered $P_{\rm A}$ (dashed line) and $P_{\rm B}$ channels (thin line). P is the geometric mean of the two filtered photometric channels.
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$\begin{figure} \par\includegraphics[width=8cm,clip]{0562f10.eps} \end{figure}$	Figure 10: From top to bottom: I₁ normalized interferogram (black), I₂ normalized interferogram (grey), and the result I of the subtraction of these two signals. For clarity, the I₁ and I₂ signals are shifted vertically by +2 and +1, respectively. The correlated noise has disappeared in the combined signal and the fringe packet appears more clearly.
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$\begin{figure} \par\includegraphics[width=8.4cm,clip]{0562f13.eps}\par\vspace*{2mm} \includegraphics[width=8.4cm,clip]{0562f14.eps} \end{figure}$	Figure 12: Squared coherence factor $\mu ^2$ as a function of the photometric signal on the fringe packet, for the sample batches obtained on $\alpha$ Cen A ( top) and $\theta$ Cen ( bottom). The dashed lines show the mean value of the series derived using the bootstrap technique.
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$\begin{figure} \par\includegraphics[width=8.1cm,clip]{0562f16.eps} \end{figure}$	Figure 14: Histogram of the $\mu ^2$ values obtained on $\theta$ Cen. No significant skewness is present.
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$\begin{figure} \par\includegraphics[width=8.1cm,clip]{0562f17.eps} \end{figure}$	Figure 15: Histogram of the $\mu ^2$ values obtained on $\alpha$ Cen A.
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$\begin{figure} \par\includegraphics[width=8cm,clip]{0562f18.eps} \end{figure}$	Figure 16: Evolution of the transfer function T² during one night (2002-05-29) on the E0-G0 baseline of the VLTI (16 m in ground length). Each symbol corresponds to a different star.
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