Constraints on the gas fraction from ROSAT PSPC observations of high-luminous clusters of galaxies
Abstract
We present a detailed and homogeneous analysis of the ROSAT PSPC surface brightness profiles of 34 clusters of galaxies with high X-ray luminosity (L_X > 1045 erg s^{-1}) and redshifts between 0.05 and 0.44. Using recent ASCA estimates of their intracluster temperature, we constrain the gas and dark matter distributions. The values of f_gas show highly significant variations between individual clusters, with a biweight location and scale of 0.172 +- 0.034 h50^{-1.5}. Combining these results with primordial nucleosynthesis calculations, and the current estimate of H_0, the above mean value implies Omega_0, m < 0.54 at the 95 per cent confidence level. This upper limit decreases to 0.31, if we take the highest significant estimate for f_gas. The average radial dependence of the gas fraction within a cluster is as r^s, with s ~0.18
- Publication:
-
19th Texas Symposium on Relativistic Astrophysics and Cosmology
- Pub Date:
- December 1998
- Bibcode:
- 1998tx19.confE.509E