On the Final State of Spherical Gravitational Collapse
  In a recent paper (FPL 13(6), 543, 2000, astro-ph/9910408), from several independent considerations we showed that GTR does not allow formation of trapped surfaces and finite mass BHs. We rediscuss here several subtle issues involved in this work. So far only the scientific critique to this work was due to Tereno (astro-ph/9905144, astro-ph/9905298) and which was answered in Mitra (astro-ph/9905175, astro-ph/9905175, astro-ph/9905329). Now Tereno (gr-qc/0111073) has also admitted that the local 3-speed of a free particle as conventionally defined by all previous authors and as measured in any coordinate system, is indeed c at the EH. Further since the acceleration SCALAR BLOWS UP at the EH, our result that there cannot be any EH at a finite R is reconfirmed. We explicitly show here that the final state of spherical collapse of very massive stars corresponds to a zero mass BH with 2M/R ->0. But at any finite epoch there would be a Eternally Collapsing Objects (ECO) of finite mass. However, if quantum back reaction in the strong gravity regime would cause a phase transition p ~ rho, there could be static ultracompact objects (UCO) of ~ 10 M (solar). Further, if the phase transition goes proceeds to p= -rho, there could be UCOs of arbitrary high mass (Mazur & Mottola, astro-ph/0109035). Both ECOs and UCOs are expected to possess strong internal magnetic field whereas the the same for a BH is zero. Robertson & Leiter (ApJ 565, 447, 2002, astro-ph/0102381) have shown that the BH candiadates may indeed possess such strong intrinsic mag field. Thus the BHCs are likely to ECOs/UCOs rather than BHs. We also discuss that there is no real evidence for detection of EH. 
Abhas Mitra (NRL, BARC, India)