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As part of the SPLASH survey of the Andromeda galaxy (M31) and its neighbors,we have obtained Keck/DEIMOS spectra of the compact elliptical (cE) satelliteM32. This is the first resolved-star kinematical study of any cE galaxy. Incontrast to previous studies that extended out to r<30"~1Re~100pc, we measurethe rotation curve and velocity dispersion profile out to r~250" and higherorder Gauss-Hermite moments out to r~70". We achieve this by combiningintegrated-light spectroscopy at small radii (where crowding/blending aresevere) with resolved stellar spectroscopy at larger radii, using spatial andkinematical information to statistically account for M31 contamination. Therotation curve and velocity dispersion profile extend well beyond the radius(r~150") where the isophotes are distorted. Unlike NGC 205, another close dwarfcompanion of M31, M32's kinematic are regular and symmetric and do not showobvious sharp gradients across the region of isophotal elongation and twists.We interpret M32's kinematics using three-integral axisymmetric dynamicalequilibrium models constructed using Schwarzschild's orbit superpositiontechnique. Models with a constant M/L can fit the data remarkably well.However, since such a model requires an increasing tangential anisotropy withradius, invoking the presence of an extended dark halo may be more plausible.Such an extended dark halo is definitely required to bind a half-dozenfast-moving stars observed at the largest radii, but these stars may not be anequilibrium component of M32. The observed regularity of the stellarkinematics, as well as the possible detection of an extended dark halo, areunexpected if M31 tides are significant at large radii. While these findings bythemselves do not rule out tidal models for cE formation, they suggest thattidal stripping may not be as significant for shaping cE galaxies as has oftenbeen argued.

Internal Stellar Kinematics of M32 from the SPLASH Survey: Dark Halo Constraints and the Formation of Compact Elliptical Galaxies