Copernicus X-Ray Observations of NGC 1275 and the Core of the Perseus Cluster

The Perseus cluster of galaxies has been studied with 0.5-1.5 keV and 1. .1 keV grazing-incidence X-ray telescope systems on the Orbiting Astronomical Observatory, Copernicus. Observations with a range of apertures (12', 6', and 2') defining the field of view reveal the presence of a compact X-ray source centered 35ff + 30" north of NGC 1275. This has less than 3' extent, and we identify the X-ray source with NGC 1275. The core of the extended cluster emission observed with Uhurn is also detected. If it is assumed that the cluster core X-ray emission distribution is independent of energy, then the X-ray intensity of NGC 1275 is percent of the total cluster emission, and may have a similar spectrum. We therefore deduce a 0.5-1.5 keV X-ray luminosity of either 1 X 10 or 2.5 X 10 ergs 1 (H0 = 50 km s ' ) for NGC 1275. We discuss the isothermal gas sphere model for the cluster core, provide upper limits in the 0.5-1.5 keV range for NGC 1265 and IC 310 which are within the cluster, and consider the compatibility of our results with other published data. Subject headings: galaxies, clusters of - X-ray sources