We use a combination of data acquired with the Advanced Camera for Survey ( ACS ) on board the Hubble Space Telescope and the Large Binocular Camera ( LBC-blue ) mounted on the Large Binocular Telescope , to sample the main sequence stars of the globular cluster NGC 5466 in the mass range 0.3 < M / M _ { \odot } < 0.8 .
We derive the cluster ’ s Luminosity Function in several radial regions , from the center of the cluster out to the tidal radius .
After corrections for incompleteness and field-contamination , this has been compared to theoretical Luminosity Functions , obtained by multiplying a simple power law Mass Function in the form dN/dm \propto m ^ { \alpha } by the derivative of the mass-luminosity relationship of the best-fit isochrone .
We find that \alpha varies from -0.6 in the core region to -1.9 in the outer region .
This fact allows us to observationally prove that the stars in NGC 5466 have experienced the effects of mass segregation .
We compare the radial variation of \alpha from the center out to 5 core radii ( r _ { c } ) in NGC 5466 and the globular cluster M10 , finding that the gradient of \alpha in the first 5r _ { c } is more than a factor of 2 shallower in NGC 5466 than in M10 , in line with the differences in the clusters ’ relaxation timescales .
NGC 5466 is dynamically younger than M10 , with two-body relaxation processes only recently starting to shape the distribution of main sequence stars .
This result fully agrees with the conclusion obtained in our previous works on the radial distribution of Blue Straggler Stars , further confirming that this can be used as an efficient clock to measure the dynamical age of stellar systems .