2002/09/12 by Stuart L. Shapiro, Masaru Shibata · 7 citations
Physics and Astronomy · #Astrophysical Phenomena and Observations #Gamma-ray bursts and supernovae #Pulsars and Gravitational Waves Research #astro-ph #gr-qc
paper · pdf · doi:10.1086/342246
published as Astrophys.J. 577 (2002) 904-908 · 5 pages, 1 figure, to appear in The Astrophysical Journal, October 1, 2002
arxiv created 2002/09/12 · openalex publication_date 2002/09/24 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
The collapse of a uniformly rotating, supermassive star (SMS) to a supermassive black hole (SMBH) has been followed recently by means of hydrodynamic simulations in full general relativity. The initial SMS of arbitrary mass M in these simulations rotates uniformly at the mass-shedding limit and is marginally unstable to radial collapse. The final black hole mass and spin have been determined to be M h / M ≈ 0.9 and J h / M ≈ 0.75. The remaining mass goes into a disk of mass M disk / M ≈ 0.1. Here we show that these black hole and disk parameters can be calculated analytically from the initial stellar density and angular momentum distribution. The analytic calculation thereby corroborates and provides a simple physical explanation for the computational discovery that SMS collapse inevitably terminates in the simultaneous formation of a SMBH and a rather substantial ambient disk. This disk arises even though the total spin of the progenitor star, J / M 2 = 0.97, is safely below the Kerr limit. The calculation performed here applies to any marginally unstable n = 3 polytrope uniformly rotating at the breakup speed, independent of stellar mass or the source of internal pressure. It illustrates how the black hole and disk parameters can be determined for the collapse of other types of stars with different initial density and rotation profiles.