Frenk1993 (2024)

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We investigate how the rms linear fluctuation in the mass distribution on scales of 8 h^-1^ Mpc^1^ (denoted by σ_8_) is constrained by the masses and ...
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We investigate how the rms linear fluctuation in the mass distribution on scales of 8 h^-1^ Mpc^1^ (denoted by σ_8_) is constrained by the masses and abundances of rich clusters of galaxies. The derived value of σ_8_ is almost independent of the shape of the fluctuation spectrum, but depends strongly on the cosmological density parameter. We find σ_8_~0.52-0.62 for a critical density universe, and σ_8_ ~1.25-1.58 for a spatially flat universe with {OMEGA}_0_ = 0.2. Our results conflict with the high amplitude inferred for an {OMEGA} = 1 cold dark matter universe from the COBE anisotropy measurements and advocated on other grounds by Couchman & Carlberg. However, our estimates of σ_8_ are consistent with alternative models which provide a good fit to the observed shape of galaxy correlations on scales up to 50 h^-1^ Mpc and match on to the COBE results on larger scales.

... Frenk 1993; Bahcall & Fan 1998). Equation 19 (19). where sigma 8 = delta M/M is the rms contrast in the mass found within a randomly placed sphere of radius ...
where 8 = M/M is the rms contrast in the mass found within a randomly placed sphere of radius 8h-1 Mpc. Since the rms fluctuation of galaxy counts is close to unity on this scale, 8 (g) 1, equation (19) says galaxies trace mass if m ~ 0.3, while biasing has to be substantial if m = 1. I have already indicated why I am skeptical of the latter. More important, Bahcall & Fan (1998) demonstrate that with the Einstein-de Sitter parameters the ACDM model normalized to fit the present cluster number density quite underpredicts the abundance of clusters at z 0.5.

Citation Carios Frenk 1993 Phys. World 6 (6) 21. Download Article PDF. Figures. Tables. References. Article information. Author affiliations. 1 Department of ...
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Cosmologists confirm COBE's cosmic credibility, Carios Frenk

(Amusing figures.) White, Navarro, Evrard, & Frenk 1993. How the baryon content of galaxy clusters suggests that Ω_m ≠ 1. Gravitational Lensing. Kaiser 1998
While I was a Ph.D. student at UC Berkeley, I organized a student reading group on ‘classic’ papers in astronomy, astrophysics, and cosmology, focused mostly on cosmological structure formation and galaxy formation. These are the papers that we found particularly insightful and didactic. Disclaimer: while this list has high purity, it is nowhere near having high completeness!

Citation Carios Frenk 1993 Phys. World 6 (6) 21. Download Article PDF. Figures. Tables. References. 1 Total downloads. Turn off MathJax Turn on MathJax. Get ...
Cosmologists confirm COBE's cosmic credibility, Carios Frenk

* = 0.20 results in b ~ 5 (1.5), while adopting the normalization of White, Efstathiou & Frenk (1993) results in b ~ 4 (1). Very interestingly, the ...

Baryonic matter constitutes a larger fraction of the total mass of rich galaxy clusters than is predicted by a combination of cosmic nucleosynthesis ...
Baryonic matter constitutes a larger fraction of the total mass of rich galaxy clusters than is predicted by a combination of cosmic nucleosynthesis considerations (light-element formation during the Big Bang) and standard inflationary cosmology. This cannot be accounted for by gravitational and dissipative effects during cluster formation. Either the density of the Universe is less than that required for closure, or there is an error in the standard interpretation of element abundances.

Cluster normalization requires that σ8,mΩ0.6 = 0.55 (White, Efstathiou & Frenk 1993). The biasing algorithms that we use are: (1) Semi-analytic: An ...