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Astron. Astrophys. 356, 418-434 (2000)

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Cosmological parameters from large scale structure observations

B. Novosyadlyj 1, R. Durrer 2, S. Gottlöber 3, V.N. Lukash 4 and S. Apunevych 1

1 Astronomical Observatory of L'viv State University, Kyryla and Mephodia str.8, 290005, L'viv, Ukraine
2 Department de Physique Théorique, Université de Genève, Quai Ernest Ansermet 24, 1211 Genève 4, Switzerland
3 Astrophysikalisches Institut Potsdam, An der Sternwarte 16, 14482 Potsdam, Germany
4 Astro Space Center of Lebedev Physical Institute of RAS, Profsoyuznaya 84/32, 117810 Moscow, Russia

Received 27 December 1999 / Accepted 11 February 2000


The possibility of determining cosmological parameters on the basis of a wide set of observational data including the Abell-ACO cluster power spectrum and mass function, peculiar velocities of galaxies, the distribution of Ly-[FORMULA] clouds and CMB temperature fluctuations is analyzed. Using a [FORMULA] minimization method, assuming [FORMULA] and no contribution from gravity waves, we show that this data set determines quite precisely the values of the spectral index n of the primordial power spectrum, baryon, cold dark matter and massive neutrino density [FORMULA], [FORMULA] and [FORMULA] respectively, the Hubble constant [FORMULA]km/s/Mpc) and the value of the cosmological constant, [FORMULA].

Varying all parameters, we found that a tilted [FORMULA]MDM model with one sort of massive neutrinos and the parameters [FORMULA], [FORMULA] ([FORMULA]), [FORMULA], [FORMULA], [FORMULA] and [FORMULA] matches observational data best.

[FORMULA] is higher for more species of massive neutrinos, [FORMULA] for two and [FORMULA] for three species. [FORMULA] raises by [FORMULA] and [FORMULA] respectively.

The 1[FORMULA] (68.3%) confidence limits on each cosmological parameter, which are obtained by marginalizing over the other parameters, are [FORMULA], [FORMULA] ([FORMULA]), [FORMULA], [FORMULA] and [FORMULA] [FORMULA]. Here [FORMULA] is the cluster bias parameter. The best-fit parameters for 31 models which are inside of [FORMULA] range of the best model are presented (Table 4).

Varying only a subset of parameters and fixing the others changes the results. In particular, if a pure matter model ([FORMULA]) is assumed, MDM with [FORMULA], three species of massive neutrinos and low [FORMULA] matches the observational data best. If a low density Universe [FORMULA] is assumed, a [FORMULA]CDM model without hot dark matter and high [FORMULA] matches the observational data best. If the primordial power spectrum is scale invariant ([FORMULA]) a low density Universe ([FORMULA]) with very little hot dark matter ([FORMULA], [FORMULA]) becomes the best fit.

It is shown also that the observational data set used here rules out the class of CDM models with [FORMULA], scale invariant primordial power spectrum, zero cosmological constant and spatial curvature at very high confidence level, [FORMULA]. The corresponding class of MDM models are ruled out at [FORMULA] C.L.

Key words: galaxies: clusters: general – cosmology: theory – cosmology: dark matter – cosmology: large-scale structure of Universe

Send offprint requests to: Bohdan Novosyadlyj

© European Southern Observatory (ESO) 2000

Online publication: April 10, 2000