All Figures

$\begin{figure} \par {\includegraphics[width=8.2cm,clip]{0146fig1.ps}\hspace*{2cm}} \end{figure}$ Figure 1: Background subtracted light curve of XRF 020427 in the 2-28 $\rm keV$ ( top) and 40-700 $\rm keV$ ( bottom) energy bands. The integration time of each bin is 1 s.
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In the text

$\begin{figure} \par\includegraphics[width=8.4cm,clip]{0146fig2.ps}\end{figure}$ Figure 2: Prompt emission spectrum of XRF 020427 fitted with a power law absorbed by the average Galactic column density along the line of sight.
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=15cm,clip]{0146fig3.ps}\end{figure}$ Figure 3: BeppoSAX /MECS images of the field of XRF 020427 accumulated during TOO 1 ( left panel) and TOO 2 ( right panel) in the 1.4-10 keV energy band. The error circle determined with the WFC is also shown in each image. This contains a source fading by a factor $\protect\ga$ 2 from the 1st to the 2nd TOO observation.
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=8cm,clip]{0146fig4.ps}\end{figure}$ Figure 4: Chandra/ACIS-S image of the field of XRF 020427 in the 0.3-7 keV energy band accumulated during TOO 1. The X-ray afterglow source, CXOU J220928.2-651932, is that at the bottom-left side of the image. The whole shown region lies inside the X-ray afterglow error circle determined with the BeppoSAX/MECS.
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=8.5cm,clip]{0146fig5.ps}\end{figure}$ Figure 5: MECS TOO 1 spectrum with only three spectral bins in order to have a sufficient number of counts/bin to use the $\chi ^2$ minimization criterion. The best fit curve with a power law model absorbed by the average Galactic hydrogen column density along the line of sight is shown. An excess count above the power law model is apparent in the second bin.
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=8.5cm,clip]{0146fig6.ps}\end{figure}$ Figure 6: MECS TOO 1 spectrum with 6 bins. The shape of the excess in the 2nd bin of Fig. 5 is shown. Also shown is the fit of the spectrum with power law model plus a Gaussian.
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=8.5cm,clip]{0146fig7.ps}\end{figure}$ Figure 7: Analysis of the ACIS-S TOO 1 spectrum: fit with a power law absorbed by the average Galactic hydrogen column density along the line of sight.
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In the text

$\begin{figure} \par\includegraphics[width=8.8cm,clip]{0146fig8.ps}\end{figure}$ Figure 8: Temporal evolution of the 2-10 keV flux of XRF 020427 from the prompt to afterglow emission. The first three points ( asterisks) correspond to the average flux measured during the prompt emission, the third point ( diamond) to the average flux measured by the MECS during the first BeppoSAX TOO, and the last two data points ( triangles) to the average fluxes measured by ACIS-S during the two Chandra TOOs. The two upper limits around 500 s were obtained with the BeppoSAX WFC, while the other with MECS. The upper limits are at 3 $\sigma$ confidence level. The continuous line is the best fit power law to the MECS + ACIS-S data (see text), the dashed line is its extrapolation back to the time of the prompt emission.
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In the text

$\begin{figure} \par {\includegraphics[width=8.2cm,clip]{0146fig1.ps}\hspace*{2cm}} \end{figure}$	Figure 1: Background subtracted light curve of XRF 020427 in the 2-28 $\rm keV$ ( top) and 40-700 $\rm keV$ ( bottom) energy bands. The integration time of each bin is 1 s.
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$\begin{figure} \par\includegraphics[width=8.4cm,clip]{0146fig2.ps}\end{figure}$	Figure 2: Prompt emission spectrum of XRF 020427 fitted with a power law absorbed by the average Galactic column density along the line of sight.
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$\begin{figure} \par\includegraphics[angle=-90,width=15cm,clip]{0146fig3.ps}\end{figure}$	Figure 3: BeppoSAX /MECS images of the field of XRF 020427 accumulated during TOO 1 ( left panel) and TOO 2 ( right panel) in the 1.4-10 keV energy band. The error circle determined with the WFC is also shown in each image. This contains a source fading by a factor $\protect\ga$ 2 from the 1st to the 2nd TOO observation.
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$\begin{figure} \par\includegraphics[angle=-90,width=8cm,clip]{0146fig4.ps}\end{figure}$	Figure 4: Chandra/ACIS-S image of the field of XRF 020427 in the 0.3-7 keV energy band accumulated during TOO 1. The X-ray afterglow source, CXOU J220928.2-651932, is that at the bottom-left side of the image. The whole shown region lies inside the X-ray afterglow error circle determined with the BeppoSAX/MECS.
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$\begin{figure} \par\includegraphics[angle=-90,width=8.5cm,clip]{0146fig5.ps}\end{figure}$	Figure 5: MECS TOO 1 spectrum with only three spectral bins in order to have a sufficient number of counts/bin to use the $\chi ^2$ minimization criterion. The best fit curve with a power law model absorbed by the average Galactic hydrogen column density along the line of sight is shown. An excess count above the power law model is apparent in the second bin.
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$\begin{figure} \par\includegraphics[angle=-90,width=8.5cm,clip]{0146fig6.ps}\end{figure}$	Figure 6: MECS TOO 1 spectrum with 6 bins. The shape of the excess in the 2nd bin of Fig. 5 is shown. Also shown is the fit of the spectrum with power law model plus a Gaussian.
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$\begin{figure} \par\includegraphics[angle=-90,width=8.5cm,clip]{0146fig7.ps}\end{figure}$	Figure 7: Analysis of the ACIS-S TOO 1 spectrum: fit with a power law absorbed by the average Galactic hydrogen column density along the line of sight.
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