We have analysed the light curve of the two brightest X-ray flares from the Galactic Center black hole , one flare observed by XMM-Newton on October 3 , 2002 ( Porquet et al . [ ] ) , and the other flare observed by Chandra on October 26 , 2000 ( Baganoff et al . [ ] ) .
The power density spectra show five distinct peaks at periods of \sim 100 s , 219 s , 700 s , 1150 s , and 2250 s common to both observations within their estimated measurement uncertainties .
The power density spectrum of the recently reported infrared flare of June 16 , 2003 ( Genzel et al . [ ] ) shows distinct peaks at two , if not three , periods ( including the 1008 \pm 120 s infrared period ) , which are consistent with the X-ray periods .
The remaining two periods could not be covered by the infrared measurements .
Each period can be identified with one of the characteristic gravitational cyclic modes associated with accretion disks , i.e .
either Lense-Thirring precession , Kepler orbital motion and the vertical and radial epicyclic oscillation modes , in such a way that a consistent value for the black hole mass of M _ { BH } = 2.72 ^ { +0.12 } _ { -0.19 } \times 10 ^ { 6 } M _ { \odot } 
and the angular momentum a = 0.9939 ^ { +0.0026 } _ { -0.0074 } is obtained .
The available data on M _ { BH } 
derived from studies of the orbital motion of the S2 ( S0-2 ) star ( Schödel et al . [ ] , Ghez et al . [ ] ) agree with our findings .
Finally we discuss some implications of the fairly high value for the angular momentum .