All Figures

$\begin{figure} \includegraphics[width=9cm,clip]{6477efig10.eps}\end{figure}$ Figure 4: Light curves in the H and V filters for five nigths in November 2005, when the observations were more intensive. Dates of observations are reported in each box. The solid line in V band - 4 Nov. box results from a linear regression analysis. The solid line in H band - 8 Nov. box connects the four points of the flare-like structure. In each box it is given a typical error bar. In V band - 4 Nov. box the light curve of one comparison star is also plotted, with a fixed enhancement of 9 mJy.
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In the text

$\begin{figure} \includegraphics[width=7cm,clip]{6477efig7.eps}\end{figure}$ Figure 10: 4 November 2005 spectrum - epoch 3. The spectral fit with a single power law yields a spectral index $\alpha$ = 1.32 $\pm$ 0.25. Error bars are comparable with symbols size.
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In the text

$\begin{figure} \includegraphics[width=9cm,clip]{6477efig13.eps}\end{figure}$ Figure 11: Different spectra of PKS 2155-304 from observations at other epochs reported in the literature. Symbols correspond to following works: filled circles: this work (13/5/2005 data), filled squares: this work (19/9/2005 data), filled up triangles: this work (4/11/2005 data), open diamonds: Bertone et al. (2000; 24/5/1996 data), open circles: Pesce et al. (1997; 19/5/1994 data, the Hamuy & Maza (1989) calibration is used), open up triangles: Zhang & Xie (1996; 5/7/1994 data), open squares: Bersanelli et al. (1992; 17/1/1987 data), open crosses: Treves et al. (1989; 1/12/1983 data), open stars: Treves et al. (1989; 11/11/1984 data), asterisks: Miller & McAlister (1983; 19/11/1981 data). Spectral index values and V magnitudes for all data sets are reported in Table 5.
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In the text

$\begin{figure} \includegraphics[width=9cm,clip]{6477efig8.eps}\end{figure}$ Figure 12: $\alpha$ vs. V plot for data reported in Fig. 11. Symbols are the same as used in Fig. 11.
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In the text

$\begin{figure} \includegraphics[width=9cm,clip]{6477efig12.eps}\end{figure}$ Figure 13: SED of PKS 2155-304 in two states, adapted from Chiappetti et al. (1999) (see the paper for details). Data from this work are also plotted. Filled triangles correspond to epoch 1 (13/5/2005 data), while filled hexagons belong to epoch 3 data (20/11/2005). Optical, UV and REM data are dereddened using E(B-V)=0.026 and parameters given by Cardelli et al. (1989).
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In the text

$\begin{figure} \includegraphics[width=7cm,clip]{6477efig7.eps}\end{figure}$	Figure 10: 4 November 2005 spectrum - epoch 3. The spectral fit with a single power law yields a spectral index $\alpha$ = 1.32 $\pm$ 0.25. Error bars are comparable with symbols size.
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$\begin{figure} \includegraphics[width=9cm,clip]{6477efig8.eps}\end{figure}$	Figure 12: $\alpha$ vs. V plot for data reported in Fig. 11. Symbols are the same as used in Fig. 11.
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$\begin{figure} \includegraphics[width=9cm,clip]{6477efig12.eps}\end{figure}$	Figure 13: SED of PKS 2155-304 in two states, adapted from Chiappetti et al. (1999) (see the paper for details). Data from this work are also plotted. Filled triangles correspond to epoch 1 (13/5/2005 data), while filled hexagons belong to epoch 3 data (20/11/2005). Optical, UV and REM data are dereddened using E(B-V)=0.026 and parameters given by Cardelli et al. (1989).
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