The mass and angular momentum distribution of simulated massive
  early-type galaxies to large radii
  We study the dark and luminous mass distributions, circular velocity curves
(CVC), line-of-sight kinematics, and angular momenta for a sample of 42
cosmological zoom simulations of massive galaxies. Using a temporal smoothing
technique, we are able to reach large radii. We find that: (i)The dark matter
halo density profiles outside a few kpc follow simple power-law models, with
flat dark matter CVCs for lower-mass systems, and rising CVCs for high-mass
haloes. The projected stellar density distributions at large radii can be
fitted by Sersic functions with n>10, larger than for typical ETGs. (ii)The
massive systems have nearly flat total CVCs at large radii, while the less
massive systems have mildly decreasing CVCs. The slope of the CVC at large
radii correlates with v_circ itself. (iii)The dark matter fractions within Re
are in the range 15-30% and increase to 40-65% at 5Re. Larger and more massive
galaxies have higher dark matter fractions. (iv)The short axes of simulated
galaxies and their host dark matter haloes are well aligned and their
short-to-long axis ratios are correlated. (v)The stellar vrms(R) profiles are
slowly declining, in agreement with planetary nebulae observations in the outer
haloes of most ETGs. (vi)The line-of-sight velocity fields v show that rotation
properties at small and large radii are correlated. Most radial profiles for
the cumulative specific angular momentum parameter lambda(R) are nearly flat or
slightly rising, with values in [0.06,0.75] from 2Re to 5Re. (vii)Stellar mass,
ellipticity at 5Re, and lambda(5Re) are correlated: the more massive systems
have less angular momentum and are rounder, as for observed ETGs. (viii)More
massive galaxies with a large fraction of accreted stars have radially
anisotropic velocity distributions outside Re. Tangential anisotropy is seen
only for galaxies with high fraction of in-situ stars. (Full abstract in PDF)
