2009                  35s               11452     J.Kim Quijano
   WFC3/UVIS   F814W     Jan 12 2010             8$\times$40s           11911     E.Sabbi
   WFC3/UVIS   F438W     Jan 14 2010             9$\times$350s          11911     E.Sabbi
   WFC3/UVIS   F814W     Jan 14 2010                  40s               11911     E.Sabbi
   WFC3/UVIS   F438W     Apr 29 2010             7$\times$350s          11911     E.Sabbi
   WFC3/UVIS   F814W     Apr 29 2010             9$\times$40s           11911     E.Sabbi
   WFC3/UVIS   F438W     Jun 30 2010             9$\times$350s          11911     E.Sabbi
   WFC3/UVIS   F814W     Jun 30 2010             4$\times$40s           11911     E.Sabbi
   WFC3/UVIS   F438W     Jul 04 2010                 350s               11911     E.Sabbi
   WFC3/UVIS   F814W     Jul 04 2010             5$\times$40s           11911     E.Sabbi
   WFC3/UVIS   F438W     Feb 15 2011                 350s               12339     E.Sabbi
   WFC3/UVIS   F438W     Mar 24 2011             8$\times$350s          12339     E.Sabbi
    ACS/WFC    F435W     Aug 18 2012      9$\times$6s$+$9$\times$339s   13066     L.J.Smith
    ACS/WFC    F435W     Aug 27 2019          42s$+$3$\times$647s       15594     V.Kozhurina-Platais

\[tab:data\]

Selection of cluster members {#sec:selection}
----------------------------

To explore the internal kinematics of the stellar populations from Gaia DR2 data we identified the sample of stars with accurate astro-photometric measurements following the method described in our previous papers [@milone2018; @cordoni2018; @cordoni2019]. In a nutshell, we first selected only stars with accurate proper motions measurements, by using both the `astrometric_gof_al` (`As_gof_al`) and the Renormalized Unit Weight Error (RUWE) parameters [see @lindegren2018]. We then selected cluster members from the proper motion vector-point diagram (VPD). We refer to @cordoni2019 for a detailed description of 