The MASSIVE Survey - V. Spatially-Resolved Stellar Angular Momentum,
Velocity Dispersion, and Higher Moments of the 41 Most Massive Local
Early-Type Galaxies
We present spatially-resolved two-dimensional stellar kinematics for the 41
most massive early-type galaxies (MK ~ 10^11.8
Msun) of the volume-limited (D < 108 Mpc) MASSIVE survey. For each galaxy, we
obtain high-quality spectra in the wavelength range of 3650 to 5850 A from the
246-fiber Mitchell integral-field spectrograph (IFS) at McDonald Observatory,
covering a 107" x 107" field of view (often reaching 2 to 3 effective radii).
We measure the 2-D spatial distribution of each galaxy's angular momentum
(lambda and fast or slow rotator status), velocity dispersion (sigma), and
higher-order non-Gaussian velocity features (Gauss-Hermite moments h3 to h6).
Our sample contains a high fraction (~80% ) of slow and non-rotators with
lambda <~ 0.2. When combined with the lower-mass ETGs in the ATLAS3D survey, we
find the fraction of slow-rotators to increase dramatically with galaxy mass,
reaching ~50% at MK ~ -25.5 mag and ~90% at MK <~ -26 mag. All of our fast
rotators show a clear anti-correlation between h3 and V/sigma, and the slope of
the anti-correlation is steeper in more round galaxies. The radial profiles of
sigma show a clear luminosity and environmental dependence: the 12 most
luminous galaxies in our sample (MK <~ -26 mag) are all brightest cluster/group
galaxies (except NGC 4874) and all have rising or nearly flat sigma profiles,
whereas five of the seven "isolated" galaxies are all fainter than MK = -25.8
mag and have falling sigma. All of our galaxies have positive average h4; the
most luminous galaxies have average h4 ~ 0.05 while less luminous galaxies have
a range of values between 0 and 0.05. Most of our galaxies show positive radial
gradients in h4, and those galaxies also tend to have rising sigma profiles. We
discuss the implications for the relationship among dynamical mass, sigma, h4,
and velocity anisotropy for these massive galaxies.Comment: 32 pages, 14 figures, 16 appendix figures. Accepted to MNRA