2011ApJ...735....3X

We propose an off-axis relativistic jet model for the Type Ic supernova SN 2007gr. Most of the energy (∼2x10⁵¹ erg) in the explosion is contained in non-relativistic ejecta which produces the supernova (SN). The optical emission comes from the decay process of ⁵⁶Ni synthesized in the bulk SN ejecta. Only very little energy (∼10⁴⁸ erg) is contained in the relativistic jet with initial velocity about 0.94 times the speed of light. The radio and X-ray emission comes from this relativistic jet. With some typical parameters of a Wolf-Rayet star (progenitor of Type Ic SN), i.e., the mass-loss rate {dot}M=1.0x 10^{-5} M_ø yr^{-1} and the wind velocity v_w= 1.5x10³ km/s together with an observing angle of θ_obs= 63°.3, we can obtain multiband light curves that fit the observations well. All the observed data are consistent with our model. Thus, we conclude that SN 2007gr contains a weak relativistic jet and we observe the jet from off-axis.