Showing papers by "Warrick J. Couch published in 1989"
TL;DR: In this article, an event that occurred in a faint member of the distant galaxy cluster AC118, at a redshift of z = 0.31, was identified and studied.
Abstract: OBSERVATIONS indicate that nearby supernova of type Ia have similar peak brightnesses, with a spread of less than 0.3 mag (ref. 1), so that they can potentially be used as 'standard candles' to estimate distances on a cosmological scale. As part of a long-term search for distant supernovae, we have identified and studied an event that occurred in a faint member of the distant galaxy cluster AC118, at a redshift of z =0.31. Extensive photometry and some spectroscopy of the event strongly supports the hypothesis that we have detected a type Ia supernova whose time-dilated light curve matches that of present-day supernovae of this class. We discuss the precision to which its maximum brightness can be ascertained, and indicate the implications that such deep supernovae searches may have for observational cosmology.
100 citations
Journal Article•
TL;DR: In this article, a supernova of type II was detected in a Galaxie spirale de type avance (V=21.7) by using photometriques and spectroscopiques.
Abstract: A la recherche d'une supernova lointaine, de type I, on a observe des amas lointains de galaxies et decouvert un phenomene du type supernova dans une galaxie faible (V=21.7). D'apres les donnees photometriques et spectroscopiques on a detecte une supernova de type II dans une galaxie spirale de type avance
2 citations
01 Jan 1989
TL;DR: In this paper, a large-scale systematic cataloguing of clusters has been undertaken, thus obliging workers to use whatever clusters have been reported in the literature, a dangerous practice given the heterogeneity of the methods used in selecting such objects.
Abstract: Galaxy cluster catalogues such as those of Abell (1958) and Zwicky et al (1961–68) have served as invaluable resources in the study of clusters and their constituent galaxies They have provided astronomers with a consistently selected collection of objects with a range of properties and at close to moderate distances (00≤z≤03) However, those interested in studying clusters at distances beyond the limits of these Schmidt plate based catalogues have not been so well provided for No deep large-scale systematic cataloguing of clusters has been undertaken, thus obliging workers to use whatever clusters have been reported in the literature — a dangerous practice given the heterogeneity of the methods used in selecting such objects