The earliest spectroscopy of the GRB 030329 afterglow with SAO RAS 6-m telescope and early spectra of core-collapse supernova

The earliest BTA (SAO RAS 6-m telescope) spectroscopic observations of the GRB 030329 optical transient (OT) are presented, which almost coincide in time with the "first break" (t similar to 0.5 day after the GRB) of the OT light curve. The beginning of spectral changes are seen as early as similar to 10-12 hours after the GRB. So, the onset of the spectral changes for t < 1 day indicates that the contribution from Type Ic supernova (SN) into the OT optical flux can be detected earlier. The properties of early spectra of GRB 030329/SN 2003dh can be consistent with a shock moving into a stellar wind formed from the pre-SN. Such a behavior (similar to that near the UV shock breakout in SNe) can be explained by the existence of a dense matter in the immediate surroundings of massive stellar GRB/SN progenitor (see Young et al., ApJ, 449 (1995) L51 and Imshennik and Nadyozhin, Usp. Fiz. Nauk, 5 (1988) 561). The urgency is emphasized of observation of early GRB/SN spectra for solving a question that is essential for understanding GRB physical mechanism: Do all long-duration gamma-ray bursts are caused by (or physically connected to) ordinary core-collapse supernovae? If clear association of normal/ordinary core-collapse SNe (SN Ib/c, and others SN types) and GRBs would be revealed in numbers of cases, we may have strong observational limits for gamma-ray beaming and for real energetics of the GRB sources.