Observations of supernovae: 1975a in NGC 2207 and 1975b in the Perseus cluster
Observations of supernovae: 1975a in NGC 2207 and 1975b in the Perseus cluster Spectroscopic, spectrophotometric, and photometric observations demonstrate that supernova 1975a, located in the unusual system NGC 2207/IC 2163, was of Type I. Observations began about 7 days before maximum light and continued until shortly after maximum. The radius of the photosphere 5 days before maximum light was of order 1 x 10/sup 15/ cm, at a temperature near 12,000/sup 0/K. An attempt to find the distance through the Baade-Wesselink method is not successful due to inadequate data. Spectroscopic evolution, on the large scale, is similar to that observed previously, but features of small wavelength extent are also observed. These observations extend the comprehensive series of spectrophotometry obtained for supernova 1972e to the era before maximum light. The supernova 1975b, in the Perseus cluster, was either of Type I, or of the class of peculiar Type I supernovae which lack the distinctive lambda 6115 feature. In either case, the observed magnitude is consistent with the distance of the cluster, despite the large redshift of the parent galaxy, and helps confirm the large velocity dispersion and mass discrepancy in the Perseus cluster.
Enter terms in the toolbar above to search the full text of this document for pages containing specific keywords.