We report D1A resolution K-band (2 km) imaging spectroscopy of the central parsec of our Galaxy. The derived radial velocities for 223 early-and late-type stars probe the nuclear mass distribution to spatial scales of 0.1 pc. We Ðnd a statistically very signiÐcant increase of projected stellar velocity dispersion from about 55 km s~1 at p D 5 pc to 180 km s~1 at p D 0.1 pc. The stars are also rotating about the dynamic center. The late-type stars follow general Galactic rotation, while the early-type stars show counter-rotation. Fitting simultaneously the observed projected surface densities and velocity dispersions, we derive the intrinsic volume densities and radial velocity dispersions as a function of distance from the dynamic center for both types of stars. We then derive the mass distribution between 0.1 and 5 pc from the Jeans equation assuming an isotropic velocity Ðeld. Our analysis requires a compact central dark mass of 2.5È3.2 ] 106 at 6È8 p signiÐcance. The dark mass has a density of 109 pc~3 or M _ , M _ greater and a mass to 2 km luminosity of º 100. The increase in mass-to-luminosity ratio can be reduced but not eliminated even if extreme anisotropic velocity destributions are considered. The dark mass cannot be a cluster of solar mass remnants (such as neutron stars). It is either a compact cluster of 10È20 black holes or a single massive black hole. M _

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Abstract. -The new MPE near infrared imaging spectrometer 3D represents a new generation of astronomical instrumentation. It is based on a 256 2 NICMOS-3 Rockwell array and can simultaneously obtain 256 H-or K-band spectra at R= 1100 or 2100 from a square 16×16 pixel field on the sky. Typical pixel scales are 0.3 /pixel or 0.5 /pixel. 3D is a combination of a novel image slicer and a liquid nitrogen cooled long slit spectrometer. It includes high definition on-axis lens optics, a high efficiency directly ruled KRS-5 grism as well as a cold closed-loop piezo-driven tilt mirror allowing full spectral sampling. The instrument efficiency including detector is 15%. Combining the advantages of imaging and spectroscopy increases the observing efficiency on key astronomical objects (e.g. galactic nuclei) by such a large factor over existing grating or Fabry-Perot spectrometers that subarcsecond near-IR spectroscopy of faint Seyferts, starbursts, quasars, or distant galaxy clusters becomes feasible for the first time with 4m-class telescopes. As a portable instrument 3D has already been successfully deployed on several 2 and 4m-class telescopes.

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