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Paper: CMB and LSS Constraints on mixed models with N > 1
Volume: 176, Observational Cosmology: The Development of Galaxy Systems
Page: 309
Authors: Bonometto, Silvio; Pierpaoli, Elena
Abstract: We compute CBR anisotropies in mixed models with different hot components, including neutrinos or volatile HDM, arising from heavier particles, decaying well before matter-radiation equivalence (lifetime ~10^4-10^7s). The CBR power spectra of these models exhibit a higher doppler peak than CDM, and the discrepancy is even stronger in volatile models which allow quite a late derelativization of HDM, even for large Ω_h. CBR experiments, together with Large Scale Structure (LSS) data, are then used to constrain the space parameter of mixed models, when values of the primeval spectral index n > 1 are also considered. Even if n > 1 is allowed, however, LSS alone prescribes that Ω_h mincir 0.30. LSS can be fitted by taking simultaneously a low derelativization redshift zder (down to ≈ 600, as is allowed in volatile models) and a high n. But CBR data from baloon-borne experiment cause a severe selection on this part of the parameter space. In fact, late derelativization and n > 1 have opposite effects on the fluctuation spectrum P(k), but sum their action on the angular spectrum C_l. Hence n magcir 1.3 seems excluded by baloon-borne experiment outputs, while a good fit of almost all CBR and LSS data is found for Ω_h values between 0.11 and 0.16, n ~1.1 and zder ~2000-5000. A smaller n is allowed, but zder < 1200 is hardly allowed.
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