All Figures

$\begin{figure} \par\includegraphics[width=6.5cm,height=5cm]{figuras_rev/fig1.ps} \end{figure}$ Figure 1: Mean star formation excess parameter $\beta= b / \langle b\rangle$ (where $\langle b\rangle$ is the mean birthrate parameter for the control sample) as a function of the tridimensional distance to the closest neighbour in the $\Lambda$ CDM experiment. Errors have been estimated by using the bootstrap resampling technique.
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In the text

$\begin{figure} \par\includegraphics[width=6.5cm,height=5cm]{figuras_rev/fig2.ps} \end{figure}$ Figure 2: Mean star formation excess parameter $\beta$ as a function of the relative tridimensional velocity for galaxy pairs with r<100 kpc h^-1 in the $\Lambda$ CDM experiment. Errors have been estimated by using the bootstrap resampling technique.
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In the text

$\begin{figure} \par\hspace*{2mm}\includegraphics[width=6.7cm,height=5cm]{figuras... ...2mm} \includegraphics[width=6.5cm,height=5cm]{figuras_rev/fig3b.ps} \end{figure}$ Figure 3: Histogram of mean stellar ages ( upper panel) and central velocities ( lower panel) for simulated galaxies in pairs ( $r < 100 \ {\rm km~ s^{-1}}$ ) separated according to their star formation activity in the $\Lambda$ CDM experiment. Dotted (solid) lines represent active (passive) star forming systems.
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In the text

$\begin{figure} \par\includegraphics[width=6.5cm,height=5cm]{figuras_rev/fig4.ps} \end{figure}$ Figure 4: Fraction of stars formed in the last 0.5 Gyr as a function of central circular velocity $V_{\rm cen}$ for passive star forming galaxies in pairs with $r < 100 \ {\rm km~ s^{-1}}$ (solid line) and in close pairs with $r < 30 \ {\rm km ~ s^{-1}}$ (dashed line) in the $\Lambda$ CDM experiment. In the insert box we show the same distributions for active star forming galaxies in pairs.
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In the text

$\begin{figure} \par\includegraphics[width=6.4cm,height=4.8cm]{figuras_rev/fig5a.... ...par\includegraphics[width=6.2cm,height=4.8cm]{figuras_rev/fig5b.ps} \end{figure}$ Figure 5: Mean star formation excess parameter $\beta$ as a function of tridimensional relative separation ( upper panel) and velocity ( lower panel) for galaxies in pairs in the $\Omega =1, \Lambda =0$ CDM simulation.
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In the text

$\begin{figure} \par\includegraphics[width=6.4cm,height=4.8cm]{figuras_rev/fig6a.... ...} \includegraphics[width=6.2cm,height=4.8cm]{figuras_rev/fig6b.ps} \end{figure}$ Figure 6: Mean star formation excess parameter $\beta$ as a function of projected distance $r_{\rm p}$ a) and $\Delta cz$ b) for galaxies in pairs in the 2D simulated catalog (solid lines). Dotted lines show the corresponding relations where spurious pairs have been removed.
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In the text

$\begin{figure} \par\includegraphics[width=6.2cm,height=4.8cm]{figuras_rev/fig7a.... ...m} \includegraphics[width=6.2cm,height=4.8cm]{figuras_rev/fig7b.ps} \end{figure}$ Figure 7: Distribution of the fraction of active (dotted line) and passive (solid line) SF galactic systems in the projected control a) and pair b) catalogs as a function of projected density estimator $\log~(\Sigma_{\rm 2D})$ .
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In the text

$\begin{figure} \par\includegraphics[width=5.3cm,height=4.8cm]{figuras_rev/fig8a.... ...m} \includegraphics[width=5.3cm,height=4.8cm]{figuras_rev/fig8b.ps} \end{figure}$ Figure 8: Histograms of the birth rate parameter (b) for galaxies in pairs (solid) and galaxies without a near companion (dashed), in high ( upper panel) and low ( lower panel) density regions.
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In the text

$\begin{figure} \par\includegraphics[width=5.3cm,height=4.9cm]{figuras_rev/fig10.ps} \end{figure}$ Figure 9: Correlation between the density estimator $\Sigma$ calculated by using the distance to the $6{\rm th}$ neighbour in the 3D galaxy distribution and in the projected one.
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In the text

$\begin{figure} \par\includegraphics[width=6.2cm,height=4.8cm]{figuras_rev/fig11a... ...} \includegraphics[width=6.2cm,height=4.8cm]{figuras_rev/fig11b.ps} \end{figure}$ Figure 10: Distribution of the fraction of galaxy-like systems in control a) and pair b) catalogs as a function of $\log~(\Sigma_{\rm 3D})$ estimated from the 3D distance to the neighbours. Simulated galaxies have been divided in two groups: active (dotted line) and passive (solid line) star forming sytems.
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In the text

$\begin{figure} \par\includegraphics[width=6cm,height=3.3cm]{figuras_rev/fig12a.p... ...m} \includegraphics[width=6cm,height=3.3cm]{figuras_rev/fig12b.ps} \end{figure}$ Figure 11: Mean star formation excess parameter $\beta$ as a function of projected distance $r_{\rm p}$ ( upper panel) and radial relative velocities ( lower panel) for galaxies in pairs of the 2D catalog in the $\Lambda$ CDM ( $\Omega=1,~ \Lambda=0.7$ ) (solid line) and SCDM ( $\Omega=1,~ \Lambda=0$ ) (dashed line). The shaded areas represent the observed relations obtained by Lambas et al. (2003) for galaxy pairs in the field in the 2dFGRS. The area width is determined by the corresponding observed dispersion.
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In the text

$\begin{figure} \par\includegraphics[width=6.5cm,height=5cm]{figuras_rev/fig1.ps} \end{figure}$	Figure 1: Mean star formation excess parameter $\beta= b / \langle b\rangle$ (where $\langle b\rangle$ is the mean birthrate parameter for the control sample) as a function of the tridimensional distance to the closest neighbour in the $\Lambda$ CDM experiment. Errors have been estimated by using the bootstrap resampling technique.
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$\begin{figure} \par\includegraphics[width=6.5cm,height=5cm]{figuras_rev/fig2.ps} \end{figure}$	Figure 2: Mean star formation excess parameter $\beta$ as a function of the relative tridimensional velocity for galaxy pairs with r<100 kpc h^-1 in the $\Lambda$ CDM experiment. Errors have been estimated by using the bootstrap resampling technique.
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$\begin{figure} \par\hspace*{2mm}\includegraphics[width=6.7cm,height=5cm]{figuras... ...2mm} \includegraphics[width=6.5cm,height=5cm]{figuras_rev/fig3b.ps} \end{figure}$	Figure 3: Histogram of mean stellar ages ( upper panel) and central velocities ( lower panel) for simulated galaxies in pairs ( $r < 100 \ {\rm km~ s^{-1}}$ ) separated according to their star formation activity in the $\Lambda$ CDM experiment. Dotted (solid) lines represent active (passive) star forming systems.
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$\begin{figure} \par\includegraphics[width=6.5cm,height=5cm]{figuras_rev/fig4.ps} \end{figure}$	Figure 4: Fraction of stars formed in the last 0.5 Gyr as a function of central circular velocity $V_{\rm cen}$ for passive star forming galaxies in pairs with $r < 100 \ {\rm km~ s^{-1}}$ (solid line) and in close pairs with $r < 30 \ {\rm km ~ s^{-1}}$ (dashed line) in the $\Lambda$ CDM experiment. In the insert box we show the same distributions for active star forming galaxies in pairs.
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$\begin{figure} \par\includegraphics[width=6.4cm,height=4.8cm]{figuras_rev/fig5a.... ...par\includegraphics[width=6.2cm,height=4.8cm]{figuras_rev/fig5b.ps} \end{figure}$	Figure 5: Mean star formation excess parameter $\beta$ as a function of tridimensional relative separation ( upper panel) and velocity ( lower panel) for galaxies in pairs in the $\Omega =1, \Lambda =0$ CDM simulation.
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$\begin{figure} \par\includegraphics[width=6.4cm,height=4.8cm]{figuras_rev/fig6a.... ...} \includegraphics[width=6.2cm,height=4.8cm]{figuras_rev/fig6b.ps} \end{figure}$	Figure 6: Mean star formation excess parameter $\beta$ as a function of projected distance $r_{\rm p}$ a) and $\Delta cz$ b) for galaxies in pairs in the 2D simulated catalog (solid lines). Dotted lines show the corresponding relations where spurious pairs have been removed.
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$\begin{figure} \par\includegraphics[width=6.2cm,height=4.8cm]{figuras_rev/fig7a.... ...m} \includegraphics[width=6.2cm,height=4.8cm]{figuras_rev/fig7b.ps} \end{figure}$	Figure 7: Distribution of the fraction of active (dotted line) and passive (solid line) SF galactic systems in the projected control a) and pair b) catalogs as a function of projected density estimator $\log~(\Sigma_{\rm 2D})$ .
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$\begin{figure} \par\includegraphics[width=5.3cm,height=4.8cm]{figuras_rev/fig8a.... ...m} \includegraphics[width=5.3cm,height=4.8cm]{figuras_rev/fig8b.ps} \end{figure}$	Figure 8: Histograms of the birth rate parameter (b) for galaxies in pairs (solid) and galaxies without a near companion (dashed), in high ( upper panel) and low ( lower panel) density regions.
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$\begin{figure} \par\includegraphics[width=5.3cm,height=4.9cm]{figuras_rev/fig10.ps} \end{figure}$	Figure 9: Correlation between the density estimator $\Sigma$ calculated by using the distance to the $6{\rm th}$ neighbour in the 3D galaxy distribution and in the projected one.
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$\begin{figure} \par\includegraphics[width=6.2cm,height=4.8cm]{figuras_rev/fig11a... ...} \includegraphics[width=6.2cm,height=4.8cm]{figuras_rev/fig11b.ps} \end{figure}$	Figure 10: Distribution of the fraction of galaxy-like systems in control a) and pair b) catalogs as a function of $\log~(\Sigma_{\rm 3D})$ estimated from the 3D distance to the neighbours. Simulated galaxies have been divided in two groups: active (dotted line) and passive (solid line) star forming sytems.
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