ИСТИНА

We present optical observations of SN 2013dx, related to the Fermi burst GRB 130702A, which occurred at red shift z=0.145. It is the second-best sampled gamma-ray burst (GRB)/supernova (SN) after SN 1998bw. The observational light curves contain more than 280 data points in the uBgrRiz filters until 88 d after the burst, and the data were collected from our observational collaboration (Maidanak Observatory, Abastumani Observatory, Crimean Astrophysical Observatory, Mondy Observatory, National Observatory of Turkey and Observatorio del Roque de los Muchachos) and from the literature. We model numerically the multicolour light curves using the one-dimensional radiation hydrodynamical code STELLA, previously widely implemented for modelling typical non-GRB SNe. The best-fitting model has the following parameters: pre-SN star mass M = 25 MSun; mass of the compact remnant MCR = 6 M_Sun; total energy of the outburst Eoburst = 3.5 x 10^52 erg; pre-supernova star radius R = 100RSun; M_Ni = 0.2 MSun, which is totally mixed through the ejecta; MO = 16.6 MSun; MSi = 1.2 MSun and MFe = 1.2 MSun, and the radiative efficiency of the SN is 0.1 per cent.