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We investigate by two-dimensional axisymmetric relativistic hydrodynamicalsimulations (1) jet propagations through an envelope of a rapidly rotating andcollapsing massive star, which is supposed to be a progenitor of long durationgamma ray bursts (GRBs), (2) breakouts and subsequent expansions into stellarwinds and (3) accompanying photospheric emissions. We find that if the enveloperotates uniformly almost at the mass shedding limit, its outer part stopscontracting eventually when the centrifugal force becomes large enough. Thenanother shock wave is formed, propagates outwards and breaks out of theenvelope into the stellar wind. Which breaks out earlier, the jet or thecentrifugal bounce-induced shock, depends on the timing of jet injection. Ifthe shock breakout occurs earlier owing to a later injection, the jetpropagation and subsequent photospheric emissions are affected substantially.We pay particular attention to observational consequences of the difference inthe timing of jet injection. We calculate optical depths to find the locationof photospheres, extracting densities and temperatures at appropriate retardedtimes from the hydrodynamical data. We show that the luminosity and observedtemperature of the photospheric emissions are both much lower than thosereported in previous studies. Although luminosities are still high enough forGRBs, the observed temperature are lower than the energy at the spectral peakexpected by the Yonetoku-relation. This may imply that energy exchanges betweenphotons and matter are terminated deeper inside or some non-thermal processesare operating to boost photon energies.

Jet propagations, breakouts and photospheric emissions in collapsing massive progenitors of long duration gamma ray bursts