The SLUGGS Survey: Wide-field Stellar Kinematics of Early-type Galaxies
  We present stellar kinematics of 22 nearby early-type galaxies (ETGs), based
on two-dimensional (2D) absorption line stellar spectroscopy out to ~2-4 R_e
(effective radii), as part of the ongoing SLUGGS Survey. The galaxies span a
factor of 20 in intrinsic luminosity, as well as a full range of environment
and ETG morphology. Our data consist of good velocity resolution (sigma_inst ~
25 km/s) integrated stellar-light spectra extracted from the individual
slitlets of custom made Keck/DEIMOS slitmasks. We extract stellar kinematics
measurements (V, sigma, h_3, and h_4) for each galaxy. Combining with
literature values from smaller radii, we present 2D spatially resolved maps of
the large-scale kinematic structure in each galaxy. We find that the kinematic
homogeneity found inside 1 R_e often breaks down at larger radii, where a
variety of kinematic behaviors are observed. While central slow rotators remain
slowly rotating in their halos, central fast rotators show more diversity,
ranging from rapidly increasing to rapidly declining specific angular momentum
profiles in the outer regions. There are indications that the outer trends
depend on morphological type, raising questions about the proposed unification
of the elliptical and lenticular (S0) galaxy families in the ATLAS^3D survey.
Several galaxies in our sample show multiple lines of evidence for distinct
disk components embedded in more slowly rotating spheroids, and we suggest a
joint photometric-kinematic approach for robust bulge-disk decomposition. Our
observational results appear generally consistent with a picture of two-phase
(in-situ plus accretion) galaxy formation.
