Free Access
Fig. 2
Aitoff projection for the sky coverage of the SDSS DR7 uniform quasar sample from Shen et al. (2011). RQQs are denoted by blue points, while the RLQs are represented by red points. See Sect. 2 for a description of the methodology employed in the selection for the RLQs.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.