2012ApJ...755L...6F

We show that the empirical E_p- L, Γ - L, E_p- Γ, and {bar}eta_γ - E_p correlations (where L is the time-averaged luminosity of the prompt emission, E_p is the spectral peak energy, Γ is the bulk Lorentz factor, and {bar}eta_γ is the emission efficiency of gamma-ray bursts, GRBs) are well consistent with the relations between the analogous parameters predicted in the photospheric radiation model of the prompt emission of GRBs. The time-resolved thermal radiation of GRB 090902B does follow the E_p-L and Γ-L correlations. A reliable interpretation of the four correlations in alternative models is still lacking. These may point toward a photospheric origin of prompt emission of some GRBs.