2010/07/20 by Andreas Kleinwächter, Hendrick Labranche, Reinhard Meinel
Physics and Astronomy · #Astrophysical Phenomena and Observations #Black Holes and Theoretical Physics #Pulsars and Gravitational Waves Research #astro-ph.HE #gr-qc #hep-th
paper · pdf · doi:10.1007/s10714-010-1135-9
published as Gen.Rel.Grav.43:1469-1486,2011 · 18 pages, 4 figures; Dedicated to Gernot Neugebauer on the occasion of his 70th birthday
arxiv created 2010/07/20 · openalex publication_date 2010/12/22 · arxiv updated 2011/04/28 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Solutions to Einstein's field equations describing rotating fluid bodies in equilibrium permit parametric (i.e. quasi-stationary) transitions to the extreme Kerr solution (outside the horizon). This has been shown analytically for discs of dust and numerically for ring solutions with various equations of state. From the exterior point of view, this transition can be interpreted as a (quasi) black hole limit. All gravitational multipole moments assume precisely the values of an extremal Kerr black hole in the limit. In the present paper, the way in which the black hole limit is approached is investigated in more detail by means of a parametric Taylor series expansion of the exact solution describing a rigidly rotating disc of dust. Combined with numerical calculations for ring solutions our results indicate an interesting universal behaviour of the multipole moments near the black hole limit.