Ariel V Sky Survey: Long-Term Monitoring of the X-Ray Emission from the Coma Cluster and NGC 4151

Abstract

Between 1974 November and 1976 February the Leicester Sky Survey Instrument on Ariel V made 31 observations of NGC 4151 and 70 observations of the Coma Cluster, each observation covering approximately 3 days. Coma (3U 1257+39) showed good evidence for having flared by a factor of 1·7 ± 0·2 in less than 3 days. This observation significantly limits the size of the X-ray emitting region.