Global Causal Structure of a Transient Black Object
  A singularity-free and spherically symmetric transient black object whose center remains always timelike, yet directly manifests a trapped region, has been constructed and numerically implemented. The exterior geometry is shown to be similar to that of a long-lived transient black hole, with a few subtle differences. The large-scale global structure of the geometry is examined through the construction of a conformal diagram, which exhibits no event horizon and bears resemblance to that of a Minkowski spacetime. Since there is no singularity within the geometry, the evolution of the exchange of information between timelike observers, including those that fall through the trapped region, can be directly explored. The dynamics of generic "standard" communications, as well as entangled communications, is exhibited through both t-versus-r and conformal spacetime diagrams. 
Tehani K. Finch and James Lindesay
gr-qc