The extended Planetary Nebula Spectrograph (ePN.S) early-type galaxy
  survey. The kinematic diversity of stellar halos and the relation between
  halo transition scale and stellar mass
  In the hierarchical two-phase formation scenario, the extended halos of early
type galaxies (ETGs) are expected to have different physical properties from
those of the galaxies' central regions. This work aims at characterizing the
kinematic properties of ETG halos using planetary nebulae (PNe) as tracers,
which allow us to overcome the limitations of absorption line spectroscopy of
continuum at low surface brightness. We present two-dimensional velocity and
velocity dispersion fields for 33 ETGs, including both fast (FRs) and slow
rotators (SRs), making this the largest kinematic survey to-date of
extragalactic PNe. The velocity fields extend out to a median 5.6 effective
radii (Re), with a range [3Re-13Re] for the PN.S ETGs. We complemented the PN
kinematics with absorption line data from the literature. We find that ETGs
typically show a kinematic transition between inner regions and halo. Estimated
transition radii in units of Re anticorrelate with stellar mass. SRs have
increased but still modest rotational support at large radii, while most of the
FRs show a decrease in rotation, due to the fading of the stellar disk in the
outer, more slowly rotating spheroid. 30% of the FRs are dominated by rotation
also at large radii. Most ETGs have flat or slightly falling halo velocity
dispersion profiles, but 15% of the sample have steeply falling profiles. 40%
of the FRs show kinematic twists, misalignments, or rotation along two axes,
indicating that they turn from oblate at the center to triaxial in the halo,
consistently with the distribution of isophote twists from extended photometry.
ETGs have more diverse kinematic properties in their halos than in the central
regions. The observed kinematic transition to the halo and its dependence on
stellar mass is consistent with LambdaCDM simulations and supports a two-phase
formation scenario. [abridged]
