All Figures

$\begin{figure} \par\includegraphics[width=17cm,clip]{3519_f1.eps} \end{figure}$ Figure 1: The Clowes-Campusano LQG ( left; 1.2<z<1.4) and the $z\simeq 0.8$ structure ( right; 0.77<z<0.93). Each quasar and Mg IIabsorber within the redshift range of the two structures are indicated by stars and circles respectively, labelled by their redshift. Double circles indicate two Mg IIsystems towards a line of sight. The boundaries of the plots match the boundaries of the AQD survey of ESO/SERC field 927 (Clowes & Campusano 1991, 1994), while the boundaries of the Mg IIsurvey (Williger et al. 2002) and the BTC field (Haines 2001) are indicated by dashed and solid boxes.
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In the text

$\begin{figure} \par\includegraphics[width=8.8cm,clip]{3519_f2.eps} \end{figure}$ Figure 2: Evolution of galaxies' V-I colours as a function of galaxy type and redshift. The solid curves represent stellar populations formed in an instantaneous burst at $z_{\rm f}=3.5$ (thick) and $z_{\rm f}=2.0$ (thin), and are thought to represent the colour evolution of massive ellipticals. The dashed and dot-dashed curves represent stellar populations with exponentially-decaying star-formation rates with time-scales ( $\tau$ ) of 1 and 5 Gyr respectively, and are thought to represent the colour evolution of disk-dominated galaxies. The points correspond to the colour of the red sequence for clusters from the surveys of SED98, S97, A93 and N01. The dotted line indicates the colour selection threshold for red galaxies at I=23.5.
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In the text

$\begin{figure} \par\includegraphics[width=8.8cm,clip]{3519_f3.eps} \end{figure}$ Figure 3: Best-fit synthetic SED to sample galaxy in EIS-DEEP field with $\textit {UBVRIJK}_{\rm s}$ photometry.
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In the text

$\begin{figure} \par\includegraphics[width=8.4cm,clip]{3519_f4.eps} \end{figure}$ Figure 4: The V-I colour distributions of the observed excess of red galaxies for the BTC field (solid curve connecting filled circles). For comparison the dotted curve shows the colour distribution of galaxies in the DLS field (scaled to fit plot), and the star-shaped symbols indicate the colour distribution of stars in the BTC field.
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In the text

$\begin{figure} \par\includegraphics[width=8.3cm,clip]{3519_f5.eps} \end{figure}$ Figure 5: The I magnitude distribution of the observed excess of red galaxies across the BTC field shown as a solid curve connecting filled circles. The dashed curve corresponds to the best-fitting Schechter function with $\alpha =-0.3$ and m_I^*=20.90. The dotted curve shows the magnitude distribution of the 563 galaxies nearest the z=0.5 cluster red sequence in the BTC data, while the star symbols indicate the magnitude distribution of stars redder than the z=0.5 cluster red sequence.
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In the text

$\begin{figure} \par\includegraphics[width=14cm,clip]{3519_f6.eps} \end{figure}$ Figure 6: Contour plot of the estimated density distribution of red galaxies in the BTC field (corresponding to $31\times27~h^{-2}~{\rm Mpc}^{2}$ at z=1.2). The dashed contour corresponds to the density of 1.65 galaxies arcmin^-2, that observed for the DLS data. The shaded regions indicate the density peaks with solid contours corresponding to overdensities of 100%, 200% and 300% in comparison to the DLS data. The four quasars at $z\sim 1.3$ are indicated by star symbols labelled by redshift. The NTT fields that targeted the four best cluster candidates at ${z\sim 1}$ are indicated by the labelled boxes.
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In the text

$\begin{figure} \par\includegraphics[width=16.8cm,clip]{3519_f7.eps} \end{figure}$ Figure 7: The V-I against I colour-magnitude diagrams for galaxies in the four NTT fields. Galaxies in the circular regions corresponding to the clusters identified in each field are indicated by squares, with those having (not having) the colours expected of early-type galaxies at the cluster redshift indicated by solid (open) symbols. For field 1 this corresponds to $z\simeq 1.2$ , and the galaxies are selected to have V-I>1.8 and $3.6<I-K_{\rm s}<4.8$ , whereas for fields 2, 3 and 4 this corresponds to $z\simeq 0.8$ and the galaxies are selected to have V-I>2.3 and $3.00<I-K_{\rm s}<3.75$ . The remaining galaxies in the fields are indicated by small crosses.
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In the text

$\begin{figure} \par\includegraphics[width=8.2cm,clip]{3519_f8.eps} \end{figure}$ Figure 8: The $I-K_{\rm s}$ colours of the cluster red sequence as a function of redshift. The solid curves predict the colour evolution of early-type galaxies as modelled by stellar populations formed in an instantaneous burst at $z_{\rm f}=3.5$ (thick) and $z_{\rm f}=2.0$ (thin). The points correspond to the colour of the red sequence for several known clusters at $z\simeq 1$ as well as clusters from the surveys of SED98, A93 and N01.
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In the text

$\begin{figure} \par\includegraphics[width=14.5cm,clip]{3519_f9.eps} \end{figure}$ Figure 9: Spatial distribution of galaxies in the four NTT fields. Each open circle indicates the location of a galaxy with the colours expected of early-type galaxies at the redshift of the cluster identified in each field, whose size indicates the galaxy's $K_{\rm s}$ magnitude, the area being proportional to the observed flux. For field 1 this corresponds to $z\simeq 1.2$ , and the galaxies are selected to have V-I>1.8 and $3.6<I-K_{\rm s}<4.8$ , whereas for fields 2, 3 and 4 this corresponds to $z\simeq 0.8$ and the galaxies are selected to have V-I>2.3 and $3.00<I-K_{\rm s}<3.75$ . In field 4 passively-evolving galaxies at $z\simeq 1.2$ are indicated by solid symbols. The nominal cluster regions used in Fig. 10 are shown by large circles. The location of each quasar is indicated by a star symbol.
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In the text

$\begin{figure} \par\includegraphics[width=16.5cm,clip]{3519_f10.eps} \end{figure}$ Figure 10: The $I-K_{\rm s}$ against $K_{\rm s}$ colour-magnitude diagrams for galaxies in the four NTT fields. Galaxies in the circular regions corresponding to the clusters identified in each field are indicated by squares, with those having (not having) the colours expected of early-type galaxies at the cluster redshift indicated by solid (open) symbols. For field 1 this corresponds to $z\simeq 1.2$ , and the galaxies are selected to have V-I>1.8 and $3.6<I-K_{\rm s}<4.8$ , whereas for fields 2, 3 and 4 this corresponds to $z\simeq 0.8$ and the galaxies are selected to have V-I>2.3 and $3.00<I-K_{\rm s}<3.75$ . The remaining galaxies in the fields are indicated by small crosses.
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In the text

$\begin{figure} \par\includegraphics[width=8.8cm,clip]{3519_f3.eps} \end{figure}$	Figure 3: Best-fit synthetic SED to sample galaxy in EIS-DEEP field with $\textit {UBVRIJK}_{\rm s}$ photometry.
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$\begin{figure} \par\includegraphics[width=8.4cm,clip]{3519_f4.eps} \end{figure}$	Figure 4: The V-I colour distributions of the observed excess of red galaxies for the BTC field (solid curve connecting filled circles). For comparison the dotted curve shows the colour distribution of galaxies in the DLS field (scaled to fit plot), and the star-shaped symbols indicate the colour distribution of stars in the BTC field.
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