  The Pseudo-Goldstone Boson (PGB) emission could provide a very efficient
mechanism for explaining the cosmic Gamma Ray Bursts (GRBs). The PGBs could be
produced during the merging of two compact objects like two neutron stars or
neutron star - black hole, and then decay into electron-positron pairs and
photons at distances ~ 100-1000 km. In this way, a huge energy (up to more than
10^{54} erg) can be deposited into the outer space with low baryon density in
the form of ultrarelativistic e^+e^- plasma, the so called fireball, which
originates the observed gamma-ray bursts. The needed ranges for the PGB
parameters are: mass of order MeV, coupling to nucleons g_{aN} ~ few x 10^{-6}
and to electrons g_{ae} ~ few x 10^{-9}. Interestingly enough, the range for
coupling constants correspond to that of the invisible axion with the
Peccei-Quinn symmetry breaking scale V ~ few x 10^5 GeV, but the mass of the
PGB is many orders of magnitude larger than what such a scale would demand to
an axion. Neither present experimental data nor astrophysical and cosmological
arguments can exclude such an ultramassive axion, however the relevant
parameters' window is within the reach of future experiments. Another exciting
point is that our mechanism could explain the association of some GRBs with
supernovae type Ib/c, as far as their progenitor stars have a radius ~ 10^4 km.
And finally, it also could help the supernova type II explosion: PGBs emitted
from the core of the collapsing star and decaying in the outer shells would
deposit a kinetic energy of the order of 10^{51} erg. In this way, emission of
such an axion-like particle could provide an unique theoretical base for
understanding the gamma ray bursts and supernova explosions.
