The SLUGGS survey: the assembly histories of individual early-type galaxies

摘要: Early-type (E and S0) galaxies may have assembled via a variety of different evolutionary pathways. Here, we investigate these pathways by comparing the stellar kinematic properties 24 early-type from SAGES Legacy Unifying Globulars GalaxieS (SLUGGS) survey with hydrodynamical simulations Naab et al. In particular, use kinematics starlight up to 4 effective radii (Re) as diagnostics galaxy inner outer regions, assign each one six assembly classes. The majority our (14/24) characteristics that indicate an history dominated gradual gas dissipation accretion many gas-rich minor mergers. Three galaxies, all S0s, they experienced major mergers in their more recent past. One additional elliptical is tentatively associated merger which results remnant low angular momentum. Pathways gas-poor (major or minor) dominate mass growth galaxies. Most SLUGGS appear grown (and size) stars mergers, late playing much smaller role. We find fraction accreted correlates mean age metallicity gradient, but not slope total density profile. briefly mention future observational modelling approaches will enhance ability accurately reconstruct histories individual present-day