All Figures

$\begin{figure} \par\includegraphics[angle=-90,width=5.55cm,clip]{4846fig1a.ps}\h... ...ce*{3mm} \includegraphics[angle=-90,width=5.55cm,clip]{4846fig1c.ps}\end{figure}$ Figure 1: Variation of the indices CN₂, C4668, and H $\beta$ as a function of galactocentric radius for the galaxy NGC 2832. The upper axes show the radial distance from the centre of the galaxy in arcseconds. The solid line represents a linear fit to the data, as described in the text. The data within 0 $.\!\!^{\prime\prime}$ 9 of the galaxy's centre were excluded from the fit to minimise the effects of seeing on the fitted gradients.
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=3.1cm,clip]{4846fig2a.ps}\hs... ...ace*{4mm} \includegraphics[angle=-90,width=3.1cm,clip]{4846fig2t.ps}\end{figure}$ Figure 2: Comparison of the Lick indices measured in the central spectra (integrated within an equivalent aperture of 4 $^{\prime \prime }$ at redshift z=0.016 - i.e., $\sim$ 1.3 kpc) and the indices obtained from the gradients integrating over the same aperture; $\sigma$ indicates the root mean square and $\Delta$ the mean offset between both measurements. The solid line indicates the 1:1 correspondence. In all cases, the mean offsets are not statistically significant.
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=8.45cm,clip]{4846fig3a.ps}\vspace*{3mm} \includegraphics[angle=-90,width=8.45cm,clip]{4846fig3b.ps}\end{figure}$ Figure 3: Index-index diagrams using the models of V06. Solid lines represent the predictions for populations of constant age ( top to bottom, 1.41, 2.00, 2.82, 3.98, 5.62, 7.98, 11.22, 15.85 Gyr), while dashed lines show populations of constant metallicity ( left to right, [M/H] = -0.68, -0.38, 0.0, +0.2). The solid circles in the figure indicate the position of the centre of the galaxies, while the lines connect with the measurements at one effective radius.
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=8.45cm,clip]{4846fig4.ps}\end{figure}$ Figure 4: Variations in the H $\beta$ and Fe4383 line-strength indices expected through changes in metallicity at a constant age of 10 Gyr (solid line) and due to variations in the age at constant solar metallicity (dashed line). The point represents the values of the gradients for the galaxy NGC 4842A with their associated error bars. The dotted lines indicate the projections of the values over the lines of constant age and constant metallicity.
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=8.45cm,clip]{4846fig5a.ps}\v... ...3mm} \par\includegraphics[angle=-90,width=8.45cm,clip]{4846fig5b.ps}\end{figure}$ Figure 5: Age and metallicity gradients obtained for the 10⁴ Monte Carlo simulations performed in the diagrams $\Delta$ H $\beta$ - $\Delta$ Mgb ( top panel) and $\Delta$ Mgb- $\Delta$ Fe4383 ( bottom panel) for NGC 4842A. The correlation of the errors is larger when the age and metallicity are inferred from the latter.
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=6.75cm,clip]{4846fig6a.ps}\v... ...3mm} \par\includegraphics[angle=-90,width=6.75cm,clip]{4846fig6c.ps}\end{figure}$ Figure 6: $\Delta$ index- $\Delta$ index diagrams combining the H $\beta$ gradient with Mgb, CN₂, and Fe4383. Solid lines indicate the slope of the predictions at constant age (10 Gyr); the dashed line shows the slope of the simple stellar population at solar metallicity. The solid circles represent the values of the line-strength gradients for the sample of galaxies in low-density environments.
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=5.5cm,clip]{4846fig7a.ps}\hs... ...ace*{3mm} \includegraphics[angle=-90,width=5.5cm,clip]{4846fig7c.ps}\end{figure}$ Figure 7: $\Delta$ index- $\Delta$ index diagrams in which we compare the Fe4383 gradients with the gradients of Mgb, CN₂, and C4668. Dashed lines indicate the expected gradients if the only parameter varying with radius is the age (assuming an invariant solar metallicity), while solid lines show the expected trends if the only parameter changing with radius is the metallicity (assuming a constant age of 10 Gyr).
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In the text

$\begin{figure} \par\mbox{\includegraphics[angle=-90,width=5.15cm,clip]{4846fig8a... ... \includegraphics[angle=-90,width=5.15cm,clip]{4846fig8e.ps} } \par\end{figure}$ Figure 8: Comparison of the metallicity gradient measured with different indicators combined with H $\beta$ , and the metallicity gradient calculated combining ten different indicators (see text for details).
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=5.5cm,clip]{4846fig9a.ps}\hs... ...ace*{3mm} \includegraphics[angle=-90,width=5.5cm,clip]{4846fig9f.ps}\end{figure}$ Figure 9: Relation between the metallicity gradients obtained in different index-index diagrams (as indicated in the brackets) and the velocity dispersion gradient for the sample of LDEGs. In the top left panel, the metallicity gradient has been obtained using a combination of ten indices, as described in Sect. 3.
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=5.5cm,clip]{4846fig10a.ps}\h... ...ce*{3mm} \includegraphics[angle=-90,width=5.5cm,clip]{4846fig10f.ps}\end{figure}$ Figure 10: Metallicity gradients obtained in different index-index diagrams (as indicated in brackets) versus the central velocity dispersion.
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=5.55cm,clip]{4846fig11a.ps}\... ...e*{3mm} \includegraphics[angle=-90,width=5.55cm,clip]{4846fig11f.ps}\end{figure}$ Figure 11: Relation of the metallicity gradient to the central age of the galaxies. When the correlation is statistically significant, a linear fit weighted by the errors in both axes is also shown. In these cases, the t parameter and the probability of no correlation (Pnc), as derived from a non-parametric Spearman rank test, are also indicated in the top-left corner of the panels. For a significance level of 0.05, a value of t larger than 1.96 indicates the presence of correlation between both variables.
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In the text

$\begin{figure} \par\includegraphics[width=8.45cm,clip]{4846fig12.ps}\end{figure}$ Figure 12: Relation between the global age and metallicity and the central velocity dispersion for galaxies in low-density environments. The solid line represents a linear fit weighted with the errors for the global data. The dashed line indicates the fit obtained for the central values reported in Paper II. Open circles represent E galaxies, while the S0 are represented by squares.
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In the text

$\begin{figure} \par\mbox{\includegraphics[angle=-90,width=6.3cm,clip]{4846fig13a... ...ad [M/H] (Mgb--H$\beta$ ) & 1.40 & 0.18 \\ \hline \end{tabular}\par\end{figure}$ Figure 13: Metallicity gradients versus central velocity dispersion for HDEGs. The different panels show the metallicity gradients obtained in different index-index diagrams (indicated between the brackets). The first panel ( top left) compares the metallicity gradients obtained as described in Sect. 3. In the case in which the correlation is statistically significant, an error weighted linear fit is also shown. The table at the bottom indicates the results of a t-test and a non-parametric Spearman rank test (see text for details).
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In the text

$\begin{figure} \par\includegraphics[angle=-90,width=8.45cm,clip]{4846fig5a.ps}\v... ...3mm} \par\includegraphics[angle=-90,width=8.45cm,clip]{4846fig5b.ps}\end{figure}$	Figure 5: Age and metallicity gradients obtained for the 10⁴ Monte Carlo simulations performed in the diagrams $\Delta$ H $\beta$ - $\Delta$ Mgb ( top panel) and $\Delta$ Mgb- $\Delta$ Fe4383 ( bottom panel) for NGC 4842A. The correlation of the errors is larger when the age and metallicity are inferred from the latter.
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$\begin{figure} \par\mbox{\includegraphics[angle=-90,width=5.15cm,clip]{4846fig8a... ... \includegraphics[angle=-90,width=5.15cm,clip]{4846fig8e.ps} } \par\end{figure}$	Figure 8: Comparison of the metallicity gradient measured with different indicators combined with H $\beta$ , and the metallicity gradient calculated combining ten different indicators (see text for details).
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$\begin{figure} \par\includegraphics[angle=-90,width=5.5cm,clip]{4846fig9a.ps}\hs... ...ace*{3mm} \includegraphics[angle=-90,width=5.5cm,clip]{4846fig9f.ps}\end{figure}$	Figure 9: Relation between the metallicity gradients obtained in different index-index diagrams (as indicated in the brackets) and the velocity dispersion gradient for the sample of LDEGs. In the top left panel, the metallicity gradient has been obtained using a combination of ten indices, as described in Sect. 3.
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$\begin{figure} \par\includegraphics[angle=-90,width=5.5cm,clip]{4846fig10a.ps}\h... ...ce*{3mm} \includegraphics[angle=-90,width=5.5cm,clip]{4846fig10f.ps}\end{figure}$	Figure 10: Metallicity gradients obtained in different index-index diagrams (as indicated in brackets) versus the central velocity dispersion.
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$\begin{figure} \par\includegraphics[width=8.45cm,clip]{4846fig12.ps}\end{figure}$	Figure 12: Relation between the global age and metallicity and the central velocity dispersion for galaxies in low-density environments. The solid line represents a linear fit weighted with the errors for the global data. The dashed line indicates the fit obtained for the central values reported in Paper II. Open circles represent E galaxies, while the S0 are represented by squares.
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