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2001ApJ...561...13B -
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Astrophys. J., 561, 13-21 (2001/November-1)
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Measuring Ω _{m} with the ROSAT deep cluster survey.
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BORGANI S., ROSATI P., TOZZI P., STANFORD S.A., EISENHARDT P.R., LIDMAN C., HOLDEN B., DELLA CECA R., NORMAN C. and SQUIRES G.
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Abstract (from CDS):
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We analyze the *ROSAT* Deep Cluster Survey (RDCS) to derive cosmological constraints from the evolution of the cluster X-ray luminosity distribution. The sample contains 103 galaxy clusters out to z≃0.85 and flux limit F_{lim}=3x10^{–14} ergs.s^{–1}.cm^{–2} (RDCS-3) in the [0.5-2.0] keV energy band, with a high-redshift extension containing four clusters at 0.90≤z≤1.26 and brighter than F_{lim}=1x10^{–14} ergs.s^{–1}.cm^{–2} (RDCS-1). We assume cosmological models to be specified by the matter density parameter Ω_{m}, the rms fluctuation amplitude at the 8 h^{–1} Mpc scale σ_{8}, and the shape parameter for the cold dark matter-like power spectrum Γ. Model predictions for the cluster mass function are converted into the X-ray luminosity function in two steps. First, we convert mass into intracluster gas temperature by assuming hydrostatic equilibrium. Then, temperature is converted into X-ray luminosity by using the most recent data on the L_{X}-T_{X} relation for nearby and distant clusters. These include the *Chandra* data for six distant clusters at 0.57≤z≤1.27. From RDCS-3 we find Ω_{m}=0.35^{+0.13}_{–0.10} and σ_{8}=0.66^{+0.06}_{–0.05} for a spatially flat universe with a cosmological constant, with no significant constraint on Γ (errors correspond to 1 σ confidence levels for three fitting parameters). Even accounting for both theoretical and observational uncertainties in the mass-X-ray luminosity conversion, an Einstein-de Sitter model is always excluded at far more than the 3 σ level. We also show that the number of X-ray-bright clusters in RDCS-1 at z>0.9 is expected from the evolution inferred at z<0.9 data.

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Abstract Copyright:
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∼

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Journal keyword(s):
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Cosmology: Cosmological Parameters - Cosmology: Theory - Cosmology: Dark Matter - Galaxies: Clusters: General - X-Rays: Galaxies
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CDS comments:
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Table 1: CDFS-CL1 = [GZW2002] XID 594.

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Simbad objects:
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7

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2021.10.18-09:23:29

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