CM4 - Tensions on LCDM cosmological model and model-independent constraints |
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Speaker |
Gómez-Valent, Adrià |
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Coauthors |
Gómez-Valent, Adrià; Amendola, Luca |
| Talk Title |
H0 from cosmic chronometers and Type Ia supernovae, with Gaussian Processes and the novel Weighted Polynomial Regression method |
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Abstract |
In this talk I will present new constraints on the Hubble parameter H0 obtained by using: (i) the available data on H(z) from cosmic chronometers (CCH); (ii) the Hubble rate data points extracted from the supernovae of Type Ia (SnIa) of the Pantheon compilation and the Hubble Space Telescope (HST) CANDELS and CLASH Multy-Cycle Treasury (MCT) programs; and (iii) the local HST measurement of H0 provided by Riess et al. (2018), H0^HST = (73.45+-1.66) km/s/Mpc. The inclusion of the most released and complete set of SnIa data allows us to reduce the uncertainty by a factor \sim 3 with respect to the result found by only considering the CCH information. Using Gaussian Processes (GPs) we obtain H0 = (67.06+-1.68) km/s/Mpc, which favors the lower range of values for H0 and is in 2.71\sigma tension with H0^HST. In addition, we present a novel method to reconstruct functions from data, which consists in a weighted sum of polynomial regressions (WPR). We apply it from a cosmographic perspective to reconstruct H(z) and estimate H0 from CCH and SnIa measurements. The result obtained with this method, H0 = (68.90+-1.96) km/s/Mpc, is fully compatible with the GPs ones. Finally, a more conservative GPs+WPR value is also provided, H0 = (68.45+-2.00) km/s/Mpc, which is still almost 2\sigma away from H0^HST. |
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