Fig. 3.
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C IV emission space with hexagons colour-coded by median He II EW for 66810 quasars in SDSS DR16 sample with redshift in z = 1.8 − 2.2 interval, having reliable C IV and He II measurements from MFICA reconstructions. Only hexagons with five or more quasars are plotted. Circles colour-coded by corresponding He II EW show the main dataset of 10 objects and four supplementary archival sources.
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