The spatial structure of the globular cluster NGC 5466

A study has been conducted of the spatial structure of the globular cluster NGC 5466 as functions of Delta B-magnitude interval and of the limiting B magnitudes used in star counts. Our analysis is based on astrometric and ph otometric measurements from photographic plates obtained with the 2-m refle ctor of the National Astronomical Observatory of Bulgaria. The differential and integrated apparent (Delta F(r) and F(r)) and spatial (Delta f(r) and f(r)) stellar-density functions are analyzed for various intervals of Delta B and limiting magnitudes down to B = 21'''. The structure of the cluster varies systematically as we proceed to fainter stars, starting from the tra nsition region between the subgiant branch to the turnoff from the main seq uence in the (V, B-V) diagram. This variation is twofold: (1) the radii of individual spatial zones of the cluster and of the cluster as a whole homol ogously increase in accordance with a single law, and (2) the stellar densi ty distribution changes-the rate of increase in the number of faint stars w ith increase in B grows as we move outward in the cluster. Empirical relati onships have been derived describing these variations and parameters defini ng the structure of the cluster.