ar X iv : a st ro - p h / 04 07 14 7 v 1 7 J ul 2 00 4 The GRB 980425 - SN 1998 bw Association in the EMBH Model

Our GRB theory, previously developed using GRB 991216 as a prototype, is here applied to GRB 980425. We fit the luminosity observed in the 40–700 keV, 2–26 keV and 2–10 keV bands by the BeppoSAX satellite. In addition the supernova SN1998bw is the outcome of an " induced gravitational collapse " triggered by GRB 980425, in agreement with the GRB-Supernova Time Sequence (GSTS) paradigm (Ruffini et al. [1]). A further outcome of this astrophysically exceptional sequence of events is the formation of a young neutron star generated by the SN1998bw event (Ruffini et al. [2]). A coordinated observational activity is recommended to further enlighten the underlying scenario of this most unique astrophysical system. Our GRB theory (Ruffini et al. [3, 4, 1, 5, 6] and references therein), previously successfully applied to GRB 991216 used as a prototype, is applied to GRB 980425 (Pian et al. [7]) and SN1998bw (Galama and et al. [8]). This event allows to test the validity of the theory over a range of energies of 6 orders of magnitude: both sources appear to be spherically symmetric and the respective total energies are E tot ≃ 5 × 10 53 ergs and E tot ≃ 10 48 ergs. The theory, therefore, explains all the observed features of the bolometric intensity variations of the afterglow as well as the spectral properties of the source and, in the specific case of GRB 980425 (Ruffini et al. [2]), it also allows to clarify the general astrophysical scenario in which the GRB actually occurs. In this system, in fact, we propose that GRB 980425 has been the trigger of a phenomenon of " induced gravitational collapse " (Ruffini et al. [1]) originating the supernova explosion and we also witness the birth of a young neutron star out of the supernova event. This extraordinary coincidence of these three astrophysical events represents an unprecedented scenario of fundamental importance in the field of relativistic astrophysics. The observational situation of this system is quite complex. In addition to the source GRB 980425 and the supernova SN1998bw, two X-ray sources have been found by BeppoSAX in the error box for the location of GRB 980425: a source S1 and a source S2 (Pian et al. [7]). Our approach is the following. We first interpret the GRB 980425 within the EMBH theory. This allows the computation of the luminosity, spectra, Lorentz gamma factors, and more generally all …