Absence of obvious tidal tails around the globular cluster NGC 6397

In this work, we use $N-$body simulations performed on GPU to trace the past 10 Gyr dynamical history of a globular cluster (GC) similar NGC~6397 in tidal field Milky Way-like galaxy and compare our simulated GCs with data from third Gaia early release. Our predict, contrast what is deduced data, that such should present strong extended tails by more than 6 ago (right after first its life), exceeding 1 kpc length, be roughly disrupted current time. We analyzed each initial conditions, as mass density parameters, well dark matter shape, argue most likely reason for discrepancy between related fact consider purely baryonic beginning model test. discuss if was initially embedded minihalo, latter could act protecting envelope, which prevents stripping luminous matter, while being itself gradually removed course evolution. This explain why an insignificant amount required describe velocity dispersion NGC~6397, up at least few half-mass radii.