Fig. 3.
NV ratios and BLR metallicity. The blue, red, and green symbols correspond to the QSO1 bins in which Matsuoka et al. (2011) distributed their QSO1 sample. Each cross represents the location of one given Lbol bin. The colours indicate ranges of increasing Lbol. The median values of QSO2 (Groups 1 and 2) are also shown for comparison with orange symbols (see text).
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