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Fig. 6


0.5–2 keV flux vs. apparent magnitude at 1450 Å. Black points indicate the 21 QSOs observed with Chandra, red points represent the 12 QSOs observed with XMM and the magenta point is the source observed with Swift-XRT. Detected QSOs are shown as filled circles while downward-pointing arrows represent 3σ upper limits.

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