Hydrogen in early spectra of the Type Ic supernova XRF060218/SN2006aj

V.V.Sokolov, E.Sonbas, A.S.Moskvitin, T.A.Fatkhullin, T.N.Sokolova,
V.N.Chernenkov


In early spectra of the X-ray burst XRF/GRB 060218 (obtained with BTA in
February 2006, Fatkhullin et al., GCN GRB Report No 4809) of type Ic we
detected a spectral detail which is interpreted as the H_alpha line (P-Cyg
absorption) component that can be connected to an envelope which usually
arises around a massive progenitor star due to stellar wind. The same
envelope was observed during the XRF/GRB burst itself as a powerful
black-body (shock break-out) in its spectrum (Campana et al., 2006,
Nature, 442, 1008).