The H0 and σ8 tensions and the scale invariant spectrum
| Autor: | Leila L. Graef, J. S. Alcaniz, Micol Benetti |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
Physics
010308 nuclear & particles physics media_common.quotation_subject Cosmic microwave background Astrophysics::Instrumentation and Methods for Astrophysics Astronomy and Astrophysics Astrophysics::Cosmology and Extragalactic Astrophysics Astrophysics Scale invariance 01 natural sciences Universe symbols.namesake Amplitude 0103 physical sciences symbols Baryon acoustic oscillations 010303 astronomy & astrophysics Weak gravitational lensing Astrophysics - Cosmology and Nongalactic Astrophysics Hubble's law media_common Free parameter |
| Zdroj: | Journal of Cosmology and Astroparticle Physics. 2018:066-066 |
| ISSN: | 1475-7516 |
| DOI: | 10.1088/1475-7516/2018/07/066 |
| Popis: | In a previous communication we showed that a joint analysis of Cosmic Microwave Background (CMB) data and the current measurement of the local expansion rate favours a model with a scale invariant spectrum (HZ) over the minimal $\Lambda$CDM scenario provided that the effective number of relativistic degrees of freedom, $N_{eff}$, is taken as a free parameter. Such a result is basically obtained due to the Hubble Space Telescope (HST) value of the Hubble constant, $H_0 = 73.24 \pm 1.74$ $\rm{km.s^{-1}.Mpc^{-1}}$ (68\% C.L.), as the CMB data alone discard the HZ+$N_{eff}$ model. Although such a model is not physically motivated by current scenarios of the early universe, observations pointing to a scale invariant spectrum may indicate that the origin of cosmic perturbations lies in an unknown physical process. Here, we extend the previous results performing a Bayesian analysis using joint CMB, HST, and Baryon Acoustic Oscillations (BAO) measurements. In order to take into account the well-known tension on the value of the fluctuation amplitude parameter, $\sigma_8$, we also consider Cluster Number counts (CN) and Weak Lensing (WL) data. We use two different samples of BAO data, which are obtained using two-point spatial (BAO 2PCF) and angular (BAO 2PACF) correlation functions. Our results show that a joint CMB+HST+BAO 2PCF analysis discards the HZP$+N_{eff}$ model with respect to the minimal $\Lambda$CDM scenario whereas the combination CMB+HST+BAO 2PACF favours the former model, even when an extended dataset with NC and WL is considered. Comment: 10 pages |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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