Ultrarelativistic black hole formation.

  title={Ultrarelativistic black hole formation.},
  author={William E. East and Frans Pretorius},
  journal={Physical review letters},
  volume={110 10},
We study the head-on collision of fluid particles well within the kinetic energy dominated regime (γ = 8 to 12) by numerically solving the Einstein-hydrodynamic equations. We find that the threshold for black hole formation is lower (by a factor of a few) than simple hoop conjecture estimates, and, moreover, near this threshold two distinct apparent horizons first form postcollision and then merge. We argue that this can be understood in terms of a gravitational focusing effect. The… CONTINUE READING