  NGC 1407 is the central elliptical in a nearby evolved galaxy group
apparently destined to become a cluster core. We use the kinematics of globular
clusters to probe the dynamics and mass profile of the group's center, out to
60 kpc (~10 R_eff) -- the most extended data set to date around an early-type
galaxy. This sample consists of 172 GC velocities, most of them newly obtained
using Keck/DEIMOS, with a few additional objects identified as DGTOs or as
IGCs. We find weak rotation in the GC system's outer parts, with the metal-poor
and metal-rich GCs misaligned. The RMS velocity profile declines rapidly to a
radius of ~20 kpc, and then becomes flat or rising to ~60 kpc. There is
evidence that the GC orbits have a tangential bias that is strongest for the
metal-poor GCs -- possibly contradicting theoretical expectations. We construct
cosmologically-motivated galaxy+dark halo dynamical models and infer a mass
within 60 kpc of ~3x10^12 M_Sun, extrapolating to a virial mass of ~6x10^13
M_Sun for a typical LCDM halo -- in agreement with results from group galaxy
kinematics. We present an independent Chandra-based analysis, whose relatively
high mass at ~20 kpc disagrees strongly with the GC-based result unless the GCs
are assumed to have a peculiar orbit distribution, and we discuss some general
comparisons between X-ray and optical results. The group's B-band mass-to-light
ratio of ~800 is extreme even for a rich galaxy cluster, much less a poor group
-- placing it among the most dark matter dominated systems in the universe, and
also suggesting a massive reservoir of baryons lurking in an unseen phase, in
addition to the nonbaryonic dark matter. We compare the kinematical and mass
properties of the NGC 1407 group to other nearby groups and clusters, and
discuss some implications of this system for structure formation.

Astrophysics