Mass and angular momentum of black holes: an overlooked effect of general relativity applied to the galactic center black hole Sgr A*

@article{Aschenbach2006MassAA,
  title={Mass and angular momentum of black holes: an overlooked effect of general relativity applied to the galactic center black hole Sgr A*},
  author={Bernd R. Aschenbach},
  journal={Chinese Journal of Astronomy and Astrophysics},
  year={2006},
  volume={6},
  pages={221-227}
}
  • B. Aschenbach
  • Published 8 March 2006
  • Physics
  • Chinese Journal of Astronomy and Astrophysics
I report the discovery of a new effect of General Relativity which is important to understand very rapidly rotating(Kerr) black holes. The orbital velocity of a test particle is no longer a monotonic function of the orbit radius when the spin of the black hole is >0.9953, but displays a local minimum-maximum structure for radii smaller than 1.8 gravitational radii. There the rate of change of the orbital velocity per radius unit equals the radial epicyclic frequency and is exactly one third of… 
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References

SHOWING 1-9 OF 9 REFERENCES
Measuring mass and angular momentum of black holes with high-frequency quasi-periodic oscillations
For the three microquasars GRO J1655-40, XTE J1550-564 and GRS 1915+105 twin high frequency quasi-periodic oscillations (HFQPOs) with a ratio of 3:2 and/or 3:1 have been measured. For a test particle…
Aschenbach effect: Unexpected topology changes in the motion of particles and fluids orbiting rapidly rotating Kerr black holes
Newtonian theory predicts that the velocity V of free test particles on circular orbits around a spherical gravity center is a decreasing function of the orbital radius r, dV/dr 0.9953, the velocity…
Near-infrared flares from accreting gas around the supermassive black hole at the Galactic Centre
TLDR
High-resolution infrared observations of Sagittarius A* reveal ‘quiescent’ emission and several flares, and traces very energetic electrons or moderately hot gas within the innermost accretion region.
Sinfoni in the galactic center : Young stars and infrared flares in the central light-month
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…
X-ray flares reveal mass and angular momentum of the Galactic Center black hole
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. \cite{P2003}), and the…
Stochastic Electron Acceleration During the Near-Infrared and X-Ray Flares in Sagittarius A*
Recent near-IR (NIR) and X-ray observations of Sagittarius A*'s spectrum have yielded several strong constraints on the transient energizing mechanism, justifying a reexamination of the stochastic…
Maximal Analytic Extension of the Kerr Metric
Kruskal's transformation of the Schwarzschild metric is generalized to apply to the stationary, axially symmetric vacuum solution of Kerr, and is used to construct a maximal analytic extension of the…
Stellar Orbits around the Galactic Center Black Hole
Wepresentnew diffraction-limitedimagesoftheGalacticcenter, obtainedwith theW.M.KeckI10mtelescope. Within0B4oftheGalaxy’scentraldarkmass,17proper-motionstars,withKmagnitudesrangingfrom 14.0to16.8,…
Rotating Black Holes: Locally Nonrotating Frames, Energy Extraction, and Scalar Synchrotron Radiation