On the extended stellar structure around NGC 288

A.E. PIATTI

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2017

0035-8711

We report on observational evidence of an extra-tidal clumpy structure around NGC\,288from an homogeneous coverage of a large area with the Pan-STARRS PS1 database.The extra-tidal star population  has been disentangled from that of the Milky Way field by using a cleaning technique that successfully reproduced the stellar density, luminosity functionand colour distributions of MW field stars. We have produced the cluster stellar density radial profile and a stellar density map from independent approaches, from which we found resultsin excellent agreement : the feature extends up to 3.5 times the cluster tidal radius. Previous works based on shallower photometric data setshave speculated on the existence of several long tidal tails, similar to that found in Pal\,5.The present outcome shows that NGC\,288 couldhardly have such tails, but favours the notion that interactions with the MW tidal fieldhas been a relatively inefficient process for stripping stars off the cluster. These resultspoint to the need of a renewed overall study of the external regions of Galacticglobular clusters (GGCs) in order to reliably characterise them. Hence, it will be possible to investigate whether there is  any connection between detectedtidal tails, extra-tidal stellar populations, extent diffuse halo-like structures  with the GGCs' dynamical histories in the Galaxy.