Convergence to a self-similar solution in general relativistic gravitational collapse

We study the spherical collapse of a perfect fluid with an equation of state P = kρ by full general relativistic numerical simulations. For 0 < k ∼ 0.036, it has been known that there exists a general relativistic counterpart of the Larson-Penston self-similar Newtonian solution. The numerical simulations strongly suggest that, in the neighborhood of the center, generic collapse converges to this solution in an approach to singularity and that self-similar solutions other than this solution, including a “critical solution” in the black hole critical behavior, are relevant only when parameters which parametrize initial data are fine-tuned. This result is supported by a mode analysis on the pertinent self-similar solutions. Since a naked singularity forms in the general relativistic Larson-Penston solution for 0 < k ∼ 0.0105, this will be the most serious known counterexample against the cosmic censorship. It also provides a strong evidence for the self-similarity hypothesis in general relativistic gravitational collapse. The direct consequence is that critical phenomena will be observed in the collapse of isothermal gas in Newton gravity and the critical exponent γ will be given by γ ≈ 0.11, though the order parameter cannot be the black hole mass.