Star counts in NGC 6397

I-band CCD images of a large area of the nearby globular cluster NGC 6397 have been used to construct a surface density profile and two luminosity and mass functions. The surface density profile extends out to 14' from the cluster center and shows no sign of a tidal cutoff. The inner profile is a power law with slope −0.8 steepening to −1.7 outside of 1'. The mass functions are for fields at 4' and 11' from the cluster center and confirm the upturn in the mass function for stars less massive than about 0.4 M ○. . There appears to be an excess of low-mass stars over higher-mass stars in the outer field with respect to the inner, in qualitative agreement with expectations for mass segregation