Gammaless GRBs?
  The Compactness Problem in GRBs has been resolved by invoking the Lorentz
factors associated with the relativistic bulk motion. This scenario applies to
GRBs where sufficient energy is converted to accelerate the ejected matter to
relativistic speeds. In some situations this may not be a possible mechanism.
Hence the gamma rays are trapped in the region. Here we look at these possible
scenarios, where the neutrino pair production process dominates, and the
neutrinos are able to escape freely. This could give a scenario where release
of neutrinos precedes the gamma ray emission, which is much attenuated,
possibly explaining why fewer GRBs are observed than what is expected.
