Free Access

Fig. 1


Sample selection of XUCS. The shadedless wedge is the observational optimal locus (clusters fit inside the Swift XRT field of view yet are not too far, so they are not too expensive in terms of exposure time). Points are high-quality clusters in the C4 catalog, red points are those that compose the XUCS sample.

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.