Final fate of the spherically symmetric collapse of a perfect fluid

The final fate of the spherically symmetric collapse of a perfect fluid which follows the gamma-law equation of state and adiabatic condition is investigated. Full general relativistic hydrodynamics is solved numerically using a retarded time coordinate, the so-called observer time coordinate. Thanks to this coordinate, the causal structure of the resultant space-time is automatically constructed. Then, it is found that a globally naked, shell-focusing singularity can occur at the center from relativistically high-density, isentropic, and time symmetric initial data if gamma less than or similar to 1.01 within the numerical accuracy. The result is free from the assumption of selfsimilarity. The upper limit of gamma with which a naked singularity can occur from generic initial data is consistent with the result of Ori and Piran based on the assumption of self-similarity. [S0556-2821(98)02720-9].