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1999MNRAS.305..834E - Mon. Not. R. Astron. Soc., 305, 834-848 (1999/June-1)
ROSAT PSPC observations of 36 high-luminosity clusters of galaxies: constraints on the gas fraction.
ETTORI S. and FABIAN A.C.
Abstract (from CDS):
Applying robust estimators, we find that the gas fraction within r500 of the clusters in our sample has a distribution centred on fgas(r500)=0.168 h50–1.5. The gas fraction ranges from 0.101 to 0.245 at the 95 per cent confidence level. The values of fgas show highly significant variations between individual clusters, which may be explained if the dark matter has a significant baryonic component. Within a cluster, the average radial dependence of the gas mass fraction increases outward as rs, with s∼0.20. Combining these results with those of primordial nucleosynthesis calculations and the current estimate of H0, the above central location implies Ω0,m0.56 at the 95 per cent confidence level. This upper limit decreases to 0.34 if we take the highest significant estimates for fgas.
A significant decrease in cluster gas fraction with redshift from the local value, fgas,0, of 0.21, found assuming Ω0,m=1, is also reduced if Ω0,m is low.
Abstract Copyright: 1999, Royal Astronomical Society
Journal keyword(s): galaxies: clusters: general - galaxies: fundamental parameters - intergalactic medium - cosmology: observations - dark matter - X-rays: galaxies
CDS comments: IRAS 09104 = ClG 0910.4+4109
Simbad objects: 43
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