We report the definite spectroscopic identification of \simeq 40 OB supergiants , giants and main sequence stars in the central parsec of the Galaxy .
Detection of their absorption lines have become possible with the high spatial and spectral resolution and sensitivity of the adaptive optics integral field spectrometer SPIFFI/SINFONI on the ESO VLT .
Several of these OB stars appear to be helium and nitrogen rich .
Almost all of the \simeq 80 massive stars now known in the central parsec ( central arcsecond excluded ) reside in one of two somewhat thick ( \langle|h| / R \rangle \simeq 0.14 ) rotating disks .
These stellar disks have fairly sharp inner edges ( R \simeq 1 \arcsec ) and surface density profiles that scale as R ^ { -2 } .
We do not detect any OB stars outside the central 0.5 pc .
The majority of the stars in the clockwise system appear to be on almost circular orbits , whereas most of those in the ‘ counter-clockwise ’ disk appear to be on eccentric orbits .
Based on its stellar surface density distribution and dynamics we propose that IRS 13E is an extremely dense cluster ( \rho _ { \mathrm { core } } \gtrsim 3 \times 10 ^ { 8 } M _ { \sun } pc ^ { -3 } ) , which has formed in the counter-clockwise disk .
The stellar contents of both systems are remarkably similar , indicating a common age of \simeq 6 \pm 2 Myr .
The K-band luminosity function of the massive stars suggests a top-heavy mass function and limits the total stellar mass contained in both disks to \simeq 1.5 \times 10 ^ { 4 } M _ { \sun } .
Our data strongly favor in situ star formation from dense gas accretion disks for the two stellar disks .
This conclusion is very clear for the clockwise disk and highly plausible for the counter-clockwise system .