부산대학교 도서관

Within the "fireshell" model, we define a "canonical GRB" light curve with two sharply different components: the proper-GRB (P-GRB), emitted when the optically thick fireshell of an electron-positron plasma originating from the phenomenon reaches transparency, and the afterglow, emitted due to the collision between the remaining optically thin fireshell and the circumburst medium (CBM). On the basis of the recent understanding of GRB970228 as the prototype for a new class of GRBs with "an occasional softer extended emission lasting tenths of seconds after an initial spikelike emission", we outline our "canonical GRB" scenario, originating from the gravitational collapse to a black hole, with special emphasis on the discrimination between "genuine" and "fake" short GRBs. Furthermore, we investigate how the GRB970228 analysis provides a theoretical explanation for the apparent absence of such a correlation for the GRBs belonging to this new class.