All Figures

$\begin{figure} \par\epsfig{figure=9446fig1.ps,width=15cm,bbllx=25mm,bblly=130mm,bburx=200mm,bbury=246mm} \end{figure}$ Figure 1: Typical spectrum of a RGB ( top panel), a SGB ( middle panel), and a MS ( bottom panel) star in the globular cluster NGC 288. The regions of the measured indices are marked by darker lines. Furthermore the positions of the prominent CaII H and K and Hydrogen lines are indicated in the top panel.
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In the text

$\begin{figure} \par\hspace*{3mm} \begin{tabular}[]{c c c} \hspace*{-0.6cm}\psfig... ...rx=195mm,bbury=246mm}\hspace*{3cm} \vspace*{0.9cm}\\ \end{tabular} \end{figure}$ Figure 2: The color magnitude diagrams for the globular clusters in our sample. Those stars for which line strength measurements are available are marked in color. We distinguish between stars of different evolutionary states. MS stars are indicated by blue squares, SGB stars by green triangles, and RGB stars by red circles. CN-weak and CN-strong stars are denoted by open and filled symbols, respectively. Note that in all diagrams the calibrated pre-image B and V magnitudes are shown. Our sample comprises clusters spanning a wide range in metallicity ( $-2.26< {\rm [Fe/H]}<-0.58 \;{\rm dex}$ ). The clusters Palomar 12 and Terzan 7 are believed to be part of the Sgr dSph, which is currently being disrupted by its tidal interaction with the Milky Way.
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In the text

$\begin{figure} \par\hspace*{5mm}\epsfig{figure=9446fig10.ps,width=8cm,bbllx=25mm,bblly=60mm,bburx=200mm,bbury=246mm} \end{figure}$ Figure 3: The distribution of the stars of the different clusters in the CN vs. M_V diagram. The left upper panel illustrates the overall distribution of our sample stars. In the lower panel we distinguished between different evolutionary states of the stars. The color coding of the data points corresponds to stars from the different clusters as indicated in the figure legend in the upper right. Whereas for the MS all clusters show roughly the same distribution, for the RGB the distribution shows a large scatter. For the clusters NGC 288 and NGC 362, a bimodal distribution in CN band strength is visible. In the lower left corner of the bottom panels the median errors of the measurements are shown.
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In the text

$\begin{figure} \par\hspace*{5mm}\epsfig{figure=9446fig11.ps,width=8cm,bbllx=25mm,bblly=150mm,bburx=200mm,bbury=246mm} \end{figure}$ Figure 4: The distribution of the stars in the CN vs. CH diagram for the RGB star in our sample clusters. The stars of different clusters are indicated by different colors as listed in Fig. 3. The left panel illustrates the overall distribution of our sample stars, with a typical error given in the lower right corner. The solid line indicated a possible differentiation between CN-strong and CN-weak stars in this diagram, drawn by eye. In right panel we calculated the mean CN and CH of both the CN-strong and CN-weak stars. The original overall distribution is plotted in gray, while the mean values are color-coded as defined before.
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In the text

$\begin{figure} \par\hspace*{4mm}\epsfig{figure=9446fig12.ps,width=8cm,bbllx=25mm,bblly=150mm,bburx=200mm,bbury=246mm} \end{figure}$ Figure 5: Left: the M_V vs. CN diagram for the RGB (red), SGB (green), and MS (blue) stars for the cluster NGC 288. The bimodal distribution is clearly visible. The dashed line illustrates the lower envelope fitted to this distribution. Right: plotted is M_V vs. the CN excess parameter ${\rm\delta CN}$ . Stars with ${\rm\delta CN}$ > 0.46 are defined as CN-strong and indicated by filled circles. CN-weak stars are indicated by open circles. The solid line indicates the separation between CN-strong and CN-weak stars.
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In the text

$\begin{figure} \par\hspace*{1.5cm}\scalebox{1}[1]{\includegraphics*[viewport=30 45 499 547]{9446fig13.ps}} \end{figure}$ Figure 6: Distributions of CN-band strength in the RGB stars of our sample clusters. The histograms of the CN-excess parameter ${\rm\delta CN}$ are plotted. The clusters are sorted by their metallicity. The two fairly metal-rich Sgr clusters are found in the two uppermost panels. The very CN-strong star in M 15 lies slightly off the RGB and therefore is probably not a cluster member.
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In the text

$\begin{figure} \par\hspace*{5mm}\epsfig{figure=9446fig14.ps,width=7.3cm,bbllx=25mm,bblly=60mm,bburx=200mm,bbury=246mm} \end{figure}$ Figure 7: Combined histograms of the CN-excess parameter for the clusters in our sample. The gray histogram comprises all eight clusters. In the black histogram Pal 12 and Ter 7, which are believed to belong to the Sgr dSph, are not included. Here we only consider stars on the lower RGB. ${\rm\delta CN}$ shows a bimodal distribution, which was fitted by two Gaussians. The minimum between the two Gaussians was chosen as the criterion to differentiate between CN-strong and CN-weak stars.
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In the text

$\begin{figure} \par\hspace*{5mm}\psfig{figure=9446fig15.ps,width=8cm,bbllx=25mm,bblly=150mm,bburx=200mm,bbury=246mm} \end{figure}$ Figure 8: The combined distributions of the CN excess parameters measured for stars on the SGB and MS. The gray histogram comprises all eight clusters. In the black histogram Pal 12 and Ter 7 are not included. The solid lines indicate the median values of the distributions. The dashed lines indicate the selection limits for CN-strong and CN-weak stars. Stars with ${\rm\delta CN}$ smaller than the position of the first dashed line are considered as CN-weak, stars with ${\rm\delta CN}$ larger than the position of the second dashed line as CN-strong.
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In the text

$\begin{figure} \par\hspace*{2mm} \begin{tabular}[]{c c} \psfig{figure=9446fig16.... ...t=18cm,bbllx=110mm,bblly=60mm,bburx=550mm,bbury=246mm}\end{tabular} \end{figure}$ Figure 9: The CN vs. M_V and CH vs. M_V diagrams for the eight clusters in our sample. We differentiate between RGB, SGB, and MS stars for all clusters. The CN-strong and CN-weak stars are marked by filled and open symbols, respectively. SGB and MS stars with intermediate ${\rm\delta CN}$ strength are plotted as crosses. For reasons of clarity these stars are only plotted in the CN vs. M_V diagrams. The median error of the measurements are given in the upper left corners of each panel. We do not plot the errors for SGB and MS stars in Pal 12 as they exceed the limit of the diagrams.
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In the text

$\begin{figure} \par\hspace*{5mm}\psfig{figure=9446fig18.ps,height=23cm,bbllx=30mm,bblly=60mm,bburx=150mm,bbury=246mm} \end{figure}$ Figure 10: The number ratio of CN-strong to CN-weak stars (r-parameter) vs. various cluster parameters (see Table 4). Our targets are indicated by the filled circles. The two results taken from the literature are marked by open triangles. Red, blue, yellow, and green colors indicate OH, YH, BD, and Sgr GCs, respectively. In the upper left corner the calculated Spearman rank correlation coefficient is given.
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In the text

$\begin{figure} \begin{tabular}{cc} \psfig{origin=rb,figure=9446fig19.ps,width=5.... ...bbllx=25mm,bblly=60mm,bburx=200mm,bbury=246mm}\\ \end{tabular}\par \end{figure}$ Figure 11: Plot of the r-parameter vs. those globular cluster parameters that showed a promising correlation in Fig. 10 or in previous studies by e.g., Smith (2002), such as ellipticity, central velocity dispersion ( $\sigma _{\rm vel}$ ), absolute brightness (M_V), and tidal radius ${r_{\rm t}}$ . We also include the results by Smith (2002) (triangles). The results of our study are plotted as filled circles. In this figure we furthermore differentiate between the different MW cluster populations. Old and young halo clusters are colored in red and blue, respectively. Bulge and disk clusters are plotted in yellow and accreted clusters from dwarf galaxies, such as the Sagittarius dSph, in green. The open blue circle indicates the alternative value of the r-parameter for M 15.
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In the text

$\begin{figure} \par\epsfig{figure=9446fig1.ps,width=15cm,bbllx=25mm,bblly=130mm,bburx=200mm,bbury=246mm} \end{figure}$	Figure 1: Typical spectrum of a RGB ( top panel), a SGB ( middle panel), and a MS ( bottom panel) star in the globular cluster NGC 288. The regions of the measured indices are marked by darker lines. Furthermore the positions of the prominent CaII H and K and Hydrogen lines are indicated in the top panel.
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$\begin{figure} \par\hspace{1.5cm}\scalebox{1}[1]{\includegraphics[viewport=30 45 499 547]{9446fig13.ps}} \end{figure}$	Figure 6: Distributions of CN-band strength in the RGB stars of our sample clusters. The histograms of the CN-excess parameter ${\rm\delta CN}$ are plotted. The clusters are sorted by their metallicity. The two fairly metal-rich Sgr clusters are found in the two uppermost panels. The very CN-strong star in M 15 lies slightly off the RGB and therefore is probably not a cluster member.
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