A Pristine Look at Extended Globular Cluster Structures

Abstract

Recent developments in Galactic Astronomy reveal that several Milky Way Globular Clusters (GCs) display extended structures, such as tails or diffuse envelopes, sometimes reaching a few hundred parsecs. The number of GCs exhibiting these features has increased since the Gaia Space Mission, which has enhanced our understanding by allowing efficient separation of member stars from foreground and background contaminants. However, Gaia does not provide metallicity data for many stars in and around GCs. The Pristine survey addresses this gap by supplying metallicities for millions of stars, enabling exploration of stellar populations at the tidal radius and beyond. This contribution examines selected GCs with extended structures and presents findings on [Fe/H] distributions beyond tidal radii, with plans for follow-up observations using the Prime Focus Spectrograph on the 8-m Subaru Telescope to advance our understanding of GC peripheral science.