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Fig. 1

image

Color–color diagram demonstrating the color selection of quasar candidates. The dashed black lines identify the regions (labeled with letters) where known quasars are found, while the green line marks the blue border of the planetary nebulae locus (Cioni et al. 2013). Our spectroscopically followed up quasars are marked with solid red dots, the non–quasars are marked with red triangles. Blue ×’s indicate the location of the VMC counterparts to the spectroscopically confirmed quasars from Kozłowski et al. (2013), selected adopting a maximum matching radius of 1 arcsec (the average separation is 0.15 ± 0.26 arcsec). Black dots are randomly drawn LMC objects (with errors in all three bands <0.1 mag) to demonstrate the locus of “normal” stars. Contaminating background galaxies are included among the black dots in regions B and C.

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