SPARTAN 1 X-Ray Observations of the Perseus Cluster: Comparison of the Iron Abundances and Temperatures in the Inner and Outer Regions of the Cluster
Abstract
X-ray observations of the Perseus cluster have been made by Spartan 1 with the objective of resolving both the spatial structure and the spectral characteristics in the 1-10 keV band. In a preliminary analysis, spectral fits have been made to the data obtained from two annular regions centered on NGC 1275. The central region was chosen to have a radius of 5' (160 kpc, H0 = 50 km s-1 Mpc-1), while the outer region was chosen to have an inner radius of 6' (190 kpc) and an outer radius of 20' (600 kpc). The inner region was found to be significantly cooler than the outer region, and the best fit temperatures were 4.2+0.2 -0.1 x 107 K and 7.1+0.8 -0.6 107 K respectively (90% confidence limits). A power-law component was needed to obtain a good fit for the central region. The best-fit iron abundances, expressed as a fraction of the solar abundance, were found to be 0.41+0.41-0.25 for the outer region and 0.81+0.26-0.16 for the inner region. These results support the hypothesis that a large fraction of the intracluster gas is the product of stellar nucleosynthesis. In conjunction with past measurements, they provide some evidence for a radial abundance gradient in the cluster.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- August 1987
- DOI:
- 10.1086/165437
- Bibcode:
- 1987ApJ...319..118U
- Keywords:
-
- Abundance;
- Galactic Clusters;
- Iron;
- Spaceborne Astronomy;
- Temperature Distribution;
- X Ray Astronomy;
- Emission Spectra;
- Line Spectra;
- Nuclear Fusion;
- Spartan Satellites;
- Spatial Distribution;
- Stellar Physics;
- Astrophysics;
- GALAXIES: ABUNDANCES;
- GALAXIES: CLUSTERING;
- GALAXIES: INDIVIDUAL NGC NUMBER: NGC 1275;
- GALAXIES: INTERGALACTIC MEDIUM;
- GALAXIES: X-RAYS