Mixed Models with n>1 and Large Scale Structure constraints

Abstract

Recent data on CBR anisotropies show a Doppler peak higher than expected in CDM cosmological models, if the spectral index $n=1$. However, CDM and LCDM models with n>1 can hardly be consistent with LSS data. Mixed models, instead, whose transfer function is naturally steeper because of free--streaming in the hot component, may become consistent with data if n>1, when Omega_h is large. This is confirmed by our detailed analysis, extended both to models with a hot component whose momentum space distribution had a thermal origin (like massive neutrinos), and to models with a non--cold component arising from heavier particle decay. In this work we systematically search models which fulfill all constraints which can be implemented at the linear level. We find that a stringent linear constraint arises from fitting the extra-power parameter Gamma. Other significant constraints arise comparing the expected abundances of galaxy clusters and high-z systems with observational data. Keeping to models with Gamma \geq 0.13, a suitable part of the space parameter still allows up to \sim 30% of hot component (it is worth outlining that our stringent criteria allow only models with 0.10 \mincir Omega_h \mincir 0.16, if n \leq 1). We also outline that models with such large non--cold component would ease the solution of the so--called baryon catastrophe in galaxy clusters.

28 pages + 9 figures, uses elsart.sty, to be published in New Astronomy

Cited by in corpus (10)

• The Cosmic Microwave Background and Particle Physics
• Neutrino constraints from future nearly all-sky spectroscopic galaxy surveys
• Constraints on the cosmic neutrino background
• The Cosmic Neutrino Background and the Age of the Universe
• Abundance and evolution of galaxy clusters in cosmological models with massive neutrino
• CMB and Large Scale Structure as a test of Mixed Models with n>1
• Cluster mass function in mixed models
• Improved Cosmological Parameter Constraints from CMB and H(z) Data
• Likelihood distribution for models with cosmological constant from COBE data
• Cluster Correlation in Mixed Models