Light Curves of the Radiation Emitted from Collapsing Surfaces

We discuss the effects of strong gravity on the observable characteristics, light curves and spectral broadening; of the radiation emitted during a finite interval of time from a relativistically collapsing object. Using a simplified model of monochromatic radiation from a freely-falling spherical surface, we demonstrate that the polar cap emission from a collapsing surface can be characterized by two successive light packets with distinctively different frequency broadening