Context. We test the theoretical predictions of several cosmological models against different observables to compare the indirect estimates of the current expansion rate of the Universe determined from model fitting with the direct measurements based on Cepheids data published recently. Aims. We perform a statistical analysis of type Ia supernova (SN Ia), Hubble parameter, and baryon acoustic oscillation data. A joint analysis of these datasets allows us to better constrain cosmological parameters, but also to break the degeneracy that appears in the distance modulus definition between H-0 and the absolute B-band magnitude of SN Ia, M-0. Methods. From the theoretical side, we considered spatially flat and curvature-free Lambda CDM, wCDM, and inhomogeneous Lemaitre-Tolman-Bondi (LTB) models. To analyse SN Ia we took into account the distributions of SN Ia intrinsic parameters. Results. For the Lambda CDM model we find that Omega(m) = 0.35 +/- 0.02, H-0 = (67.8 +/- 1.0) km s(-1) Mpc(-1), while the corrected SN absolute magnitude has a normal distribution N (19.13; 0.11). The wCDM model provides the same value for Omega(m), while H-0 = (66.5 +/- 1.8) km s(-1) Mpc(-1) and w = -0.93 +/- 0.07. When an inhomogeneous LTB model is considered, the combined fit provides H-0 = (64.2 +/- 1.9) km s(-1) Mpc(-1). Conclusions. Both the Akaike information criterion and the Bayes factor analysis cannot clearly distinguish between Lambda CDM and wCDM cosmologies, while they clearly disfavour the LTB model. For the Lambda CDM, our joint analysis of the SN Ia, the Hubble parameter, and the baryon acoustic oscillation datasets provides H-0 values that are consistent with cosmic microwave background (CMB)-only Planck measurements, but they di ff er by 2.5 sigma from the value based on Cepheids data.

Lukovic, V., D'Agostino, R., Vittorio, N. (2016). Is there a concordance value for H-0?. ASTRONOMY & ASTROPHYSICS, 595 [10.1051/0004-6361/201628217].

Is there a concordance value for H-0?

VITTORIO, NICOLA
2016

Abstract

Context. We test the theoretical predictions of several cosmological models against different observables to compare the indirect estimates of the current expansion rate of the Universe determined from model fitting with the direct measurements based on Cepheids data published recently. Aims. We perform a statistical analysis of type Ia supernova (SN Ia), Hubble parameter, and baryon acoustic oscillation data. A joint analysis of these datasets allows us to better constrain cosmological parameters, but also to break the degeneracy that appears in the distance modulus definition between H-0 and the absolute B-band magnitude of SN Ia, M-0. Methods. From the theoretical side, we considered spatially flat and curvature-free Lambda CDM, wCDM, and inhomogeneous Lemaitre-Tolman-Bondi (LTB) models. To analyse SN Ia we took into account the distributions of SN Ia intrinsic parameters. Results. For the Lambda CDM model we find that Omega(m) = 0.35 +/- 0.02, H-0 = (67.8 +/- 1.0) km s(-1) Mpc(-1), while the corrected SN absolute magnitude has a normal distribution N (19.13; 0.11). The wCDM model provides the same value for Omega(m), while H-0 = (66.5 +/- 1.8) km s(-1) Mpc(-1) and w = -0.93 +/- 0.07. When an inhomogeneous LTB model is considered, the combined fit provides H-0 = (64.2 +/- 1.9) km s(-1) Mpc(-1). Conclusions. Both the Akaike information criterion and the Bayes factor analysis cannot clearly distinguish between Lambda CDM and wCDM cosmologies, while they clearly disfavour the LTB model. For the Lambda CDM, our joint analysis of the SN Ia, the Hubble parameter, and the baryon acoustic oscillation datasets provides H-0 values that are consistent with cosmic microwave background (CMB)-only Planck measurements, but they di ff er by 2.5 sigma from the value based on Cepheids data.
Pubblicato
Rilevanza nazionale
Articolo
Sì, ma tipo non specificato
Settore FIS/05 - Astronomia e Astrofisica
English
cosmological parameters; distance scale; dark matter; dark energy
http://dx.medra.org/10.1051/0004-6361/201628217
Lukovic, V., D'Agostino, R., Vittorio, N. (2016). Is there a concordance value for H-0?. ASTRONOMY & ASTROPHYSICS, 595 [10.1051/0004-6361/201628217].
Lukovic, V; D'Agostino, R; Vittorio, N
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2108/179617
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