Astronomy & Astrophysics

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$\begin{figure} \par\includegraphics[width=8.8cm,clip]{3365fig1.ps} \end{figure}$ Figure 1: Observed energy distribution of QSO 1157+3143 in the optical (from CAFOS) and in the UV (STIS/HST). The inset shows the model continuum predicted from a QSO power law spectrum and a Lyman limit system at z = 2.77 with $\log N_{H {\sc i}} = 18.3$ . Vertical bars show the locations of the Lyman limit systems at z = 2.77 and z = 2.94.
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In the text

$\begin{figure} \par\includegraphics[width=8.8cm,clip]{3365fig3.ps} \end{figure}$ Figure 2: He II 304 Å absorption in QSO 1157+3143.
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In the text

$\begin{figure} \par\includegraphics[width=8.8cm,clip]{3365fig4.ps} \end{figure}$ Figure 3: Normalized STIS spectrum in comparison with Ly $\beta$ to Ly $\delta$ of a model Lyman limit system at z = 0.299 with $\log N(\mbox{H {\sc i}}) = 17.0$ and $b = 33~{\rm km~s}^{-1}$ .
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In the text

$\begin{figure} \par\includegraphics[width=13.5cm,clip]{3365fig2.ps} \end{figure}$ Figure 4: a) ( Upper) Overlay of the Ly $\alpha$ absorption of He II (from HST/STIS, bottom) and of H I (Keck/HIRES, top). Wavelengths for the H I data are divided by 4.00178 to align them with the He II data. The strong Ly $\alpha$ lines belonging to strong metal absorption systems (cf. text) are marked. b) ( lower) Overlay of the He II Ly $\alpha$ absorption (thick) and of the He II model absorption (thin: $\eta = 80$ , dashed: $\eta = 1000$ ). The mean uncertainty per pixel is 0.03 in case of $\eta = 80$ and 0.005 for $\eta = 1000$ , respectively. The opacity gaps (voids) I to V and the lowest z black trough (A) are marked. The dotted line represents the error of the STIS data.
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In the text

$\begin{figure} \par\includegraphics[width=8.8cm,clip]{3365fig1.ps} \end{figure}$	Figure 1: Observed energy distribution of QSO 1157+3143 in the optical (from CAFOS) and in the UV (STIS/HST). The inset shows the model continuum predicted from a QSO power law spectrum and a Lyman limit system at z = 2.77 with $\log N_{H {\sc i}} = 18.3$ . Vertical bars show the locations of the Lyman limit systems at z = 2.77 and z = 2.94.
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$\begin{figure} \par\includegraphics[width=8.8cm,clip]{3365fig3.ps} \end{figure}$	Figure 2: He II 304 Å absorption in QSO 1157+3143.
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$\begin{figure} \par\includegraphics[width=8.8cm,clip]{3365fig4.ps} \end{figure}$	Figure 3: Normalized STIS spectrum in comparison with Ly $\beta$ to Ly $\delta$ of a model Lyman limit system at z = 0.299 with $\log N(\mbox{H {\sc i}}) = 17.0$ and $b = 33~{\rm km~s}^{-1}$ .
Open with DEXTER