The peculiar type Ia supernova SN 1997br in ESO576-G40 was extensively observed at Beijing Astronomical Observatory (BAO) and Lick Observatory. In this paper, we present and discuss the BV RI photometry and the spectra collected over three months, starting from 9 days before maximum brightness.The light curves of SN 1997br are similar to those of SN 1991T, with slow decline rates after the B maximum. Well sampled data before the B maximum show unambiguously that SN 1997br rises more slowly and has a wider peak than normal type Ia supernovae. The optical color evolution of SN 1997br is also similar to that of SN 1991T. We estimate the extinction of SN 1997br to be E(B − V )=0.35±0.10 by comparing its BV RI light curves to those of SN 1991T and by measuring the equivalent width of interstellar Na I D absorption lines.We have conducted a thorough comparison of the spectroscopic evolution of SN 1997br, SN 1991T, and SN 1994D. Although SN 1997br is generally very similar to SN 1991T, it shows some interesting differences at various epochs. Spectra of SN 1997br seem to indicate an earlier transition to the dominant phase of Fe peak elements after the B maximum. Si II lines in SN 1997br show a very short duration after the B maximum.We discuss the implications of our observations of SN 1997br for models of type Ia supernovae. Specifically, we suggest that some SNe Ia may result from decelerated detonations of white dwarfs.

We report the discovery of two new Wolf-Rayet (WR) galaxies: Mrk 1039, and F08208+2816.Two broad WR bumps at 5808Å and 4650Å indicate the presence of WCE and WNL star population in all two sources. We also confirm the presence of WR features in Mrk 35, previously detected in a different position. The observed equivalent width of the WR bump at 4650Å and the derived number ratios of WR/(WR+O) imply that star formation in these sources takes place in short burst duration. Comparisons with the recent models of WR populations in young starbursts with the observed EW(He ii λ4686)/EW(C iv λ5808)/EW(WRbump) and their relative intensities provide an indication that the stellar initial mass function in some WR galaxies might not be Salpeter-like. It is interesting to find that the luminous IRAS source, F08208+2816, has little dust reddening, probably because of the existence of a powerful superwind. By comparisons with other starbursts observed with the Hopkins Ultraviolet Telescope, F08208+2816 as a merging system renders a chance to study the contribution from young starbursts to the UV background radiation in universe.