Tidal Tails around Globular Clusters: Are They a Good Tracer of Cluster Orbits?

We present the results of detailed N-body simulations of clusters moving in arealistic Milky Way (MW) potential. The strong interaction with the bulge andthe disk of the Galaxy leads to the formation of tidal tails, emanating fromopposite sides of the cluster. Some characteristic features in the morphologyand orientation of these streams are recognized and intepreted. The tails havea complex morphology, in particular when the cluster approaches itsapogalacticon, showing multiple ``arms'' in remarkable similarity to thestructures observed around NGC 288 and Willman 1. Actually, the tails aregenerally good tracers of the cluster path quite far from the cluster center(>7--8 tidal radii), while on the smaller scale they are mainly pointing in thedirection of the Galaxy center. In particular, the orientation of the innerpart of the tails is highly correlated to the cluster orbital phase and to thelocal orbital angular acceleration. This implies that, in general, the orbitalpath cannot be estimated directly from the orientation of the tails, unless asufficient large field around the cluster is available.Comment: Latex file in the AASTEX standard; 15 pages, 8 figures, 3 tables. Paper accepted on dec. 31 2006 for publication on ApJ, main journa