The SAGES Legacy Unifying Globulars and GalaxieS Survey (SLUGGS): Sample definition, methods, and initial results

摘要: We introduce and provide the scientific motivation for a wide-field photometric spectroscopic chemodynamical survey of nearby early-type galaxies (ETGs) their globular cluster (GC) systems. The SAGES Legacy Unifying Globulars GalaxieS (SLUGGS) is being carried out primarily with Subaru/Suprime-Cam Keck/DEIMOS. former provides deep gri imaging over 900 arcmin2 field-of-view to characterize GC host galaxy colors spatial distributions, identify targets. NIR Ca II triplet line-of-sight velocities metallicities typically ~8 R e, ~15 e in some cases. New techniques extract integrated stellar kinematics large radii (~2-3 e) are used concert data create two-dimensional (2D) velocity metallicity maps comparison simulations formation. advantages SLUGGS compared other, complementary, 2D-chemodynamical surveys its superior resolution, radial extent, multiple halo tracers. describe sample 25 ETGs, selection criteria GCs, observing strategies, reduction techniques, modeling methods. observations nearly complete more than 30 papers have so far been published using data. Here we summarize initial results, including signatures two-phase assembly, evidence bimodality, novel framework formation extended star clusters ultracompact dwarfs. An overview current constraints on systems points separate, situ modes at high redshifts metal-poor metal-rich GCs.