The SLUGGS Survey: The Assembly Histories of Individual Early-type
  Galaxies
  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 of 24 early-type galaxies from the SLUGGS survey
with the hydrodynamical simulations of Naab et al. (2014). In particular, we
use the kinematics of starlight up to 4 effective radii (R$_e$) as diagnostics
of galaxy inner and outer regions, and assign each galaxy to one of six Naab et
al. assembly classes.
  The majority of our galaxies (14/24) have kinematic characteristics that
indicate an assembly history dominated by gradual gas dissipation and accretion
of many gas-rich minor mergers. Three galaxies, all S0s, indicate that they
have experienced gas-rich major mergers in their more recent past. One
additional elliptical galaxy is tentatively associated with a gas-rich merger
which results in a remnant galaxy with low angular momentum. Pathways dominated
by gas-poor (major or minor) mergers dominate the mass growth of six galaxies.
Most SLUGGS galaxies appear to have grown in mass (and size) via the accretion
of stars and gas from minor mergers, with late major mergers playing a much
smaller role.
  We find that the fraction of accreted stars correlates with the stellar mean
age and metallicity gradient, but not with the slope of the total mass density
profile. We briefly mention future observational and modelling approaches that
will enhance our ability to accurately reconstruct the assembly histories of
individual present day galaxies.
