2005ApJ...628..246E

We report on 75 mas resolution, near-IR imaging spectroscopy within the central 30 lt-days of the Galactic center, taken with the new adaptive optics-assisted integral-field spectrometer SINFONI on the ESO VLT. To a limiting magnitude of K∼16, 9 of 10 stars in the central 0".4, and 13 of 17 stars out to 0".7 from the central black hole have spectral properties of B0-B9 main-sequence stars. Based on the 2.1127 µm He I line width, all brighter early-type stars have normal rotation velocities, similar to solar neighborhood stars. We combine the new radial velocities with SHARP/NACO astrometry to derive improved three-dimensional stellar orbits for six of these ``S stars'' in the central 0".5. Their orientations in space appear random. Their orbital planes are not co-aligned with those of the two disks of massive young stars 1"-10" from Sgr A*. We can thus exclude the hypothesis that the S stars as a group inhabit the inner regions of these disks. They also cannot have been located/formed in these disks and then migrated inward within their planes. From the combination of their normal rotation and random orbital orientations, we conclude that the S stars were most likely brought into the central light-month by strong individual scattering events. The updated estimate of distance to the Galactic center from the S2 orbit fit is R<sub>0</sub>=7.62±0.32 kpc, resulting in a central mass value of (3.61±0.32)x10<sup>6</sup> M<sub>☉</sub>. We happened to catch two smaller flaring events from Sgr A* during our spectral observations. The 1.7-2.45 µm spectral energy distributions of these flares are fit by a featureless, ``red'' power law of spectral index α'=-4±1 (S_ν~ν^α'). The observed spectral slope is in good agreement with synchrotron models in which the infrared emission comes from accelerated, nonthermal, high-energy electrons in a radiatively inefficient accretion flow in the central R∼10R_S region.