The ATLAS3D project - II. Morphologies, kinemetric features and
  alignment between photometric and kinematic axes of early-type galaxies
  [Abridged] We use the ATLAS3D sample of 260 early-type galaxies (ETGs) to
study the apparent kinematic misalignment angle, Psi, defined as the angle
between the photometric and kinematic major axis. We find that 71% of nearby
ETGs are strictly aligned systems (Psi > 5 deg), an additional 14% have 5 < Psi
< 10 deg and 90% of galaxies have Psi < 15 deg. Taking into account measurement
uncertainties, 90% of galaxies can be considered aligned to better than 5 deg,
suggesting that only a small fraction of early-type galaxies (~10%) are not
consistent with axisymmetry within the projected half-light radius. We identify
morphological features such as bars and rings (30%), dust structures (16%),
blue nuclear colours (6%) and evidence of interactions (8%). We use kinemetry
to analyse the mean velocity maps and separate galaxies in two broad types of
regular and non-regular rotators. We find 82% of regular rotators and 17%
non-regular rotators, with 2 galaxies that we were not able to classify due to
data quality. The non-regular rotators are typically found in dense regions and
are massive. The majority of galaxies do not have any specific kinemetric
features, but we highlight here the frequency of the kinematically distinct
cores (7%) and the aligned double peaks in the velocity dispersion maps (4%).
Most of the galaxies that are misaligned have complex kinematics and are
non-regular rotators. While the trends are weak, there is a tendency that large
values of Psi are found in galaxies at intermediate environmental densities and
among the most massive galaxies in the sample. We suggest that the most common
formation mechanism for ETGs preserves the axisymmetry of the disk progenitors.
Less commonly, the formation process results in a triaxial galaxy with much
lower net angular momentum.
