Free Access

Fig. 6


2MAst HQb5 (left) and UCAC4 HQ (right) proper motions in a field centred on the globular cluster NGC 6121 (M 4). All stars within 30 arcmin from the cluster centre are plotted. In both panels, the circle marks the mean cluster motion as measured in Paper II. The radius of the circle is 15 mas/yr, corresponding to the size of our circular proper motion bins. The offset of both field and cluster stars in the right panel illustrates the regional systematic proper motion differences between the catalogues discussed in Sect. 2.3.

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.