BAO signatures in the 2-point angular correlations and the Hubble tension
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Regular Article - Theoretical Physics
BAO signatures in the 2-point angular correlations and the Hubble tension Rafael C. Nunes1,a , Armando Bernui2,b 1 2
Divisão de Astrofísica, Instituto Nacional de Pesquisas Espaciais, Avenida dos Astronautas 1758, São José dos Campos, SP 12227-010, Brazil Observatório Nacional, Rua General José Cristino 77, São Cristóvão, Rio de Janeiro, RJ 20921-400, Brazil
Received: 25 September 2020 / Accepted: 24 October 2020 © The Author(s) 2020
Abstract An observational tension on estimates of the Hubble parameter, H0 , using early and late Universe information, is being of intense discussion in the literature. Additionally, it is of great importance to measure H0 independently of CMB data and local distance ladder method. In this sense, we analyze 15 measurements of the transversal BAO scale, θBAO , obtained in a weakly model-dependent approach, in combination with other data sets obtained in a model-independent way, namely, Big Bang Nucleosynthesis (BBN) information, 6 gravitationally lensed quasars with measured time delays by the H0LiCOW team, and measures of cosmic chronometers (CC). We find H0 = 74.88+1.9 −2.1 −1 Mpc−1 from km s−1 Mpc−1 and H0 = 72.06+1.2 km s −1.3 θ B AO +BBN+H0LiCOW and θ B AO +BBN+CC, respectively, in fully accordance with local measurements. Moreover, we estimate the sound horizon at drag epoch, rd , independent of CMB data, and find rd = 144.1+5.3 −5.5 Mpc (from +2.7 Mpc (from θ B AO +BBN+H0LiCOW) and rd = 150.4−3.3 θ B AO +BBN+CC). In a second round of analysis, we test how the presence of a possible spatial curvature, k , can influence the main results. We compare our constraints on H0 and rd with other reported values. Our results show that it is possible to use a robust compilation of transversal BAO data, θ B AO , jointly with other model-independent measurements, in such a way that the tension on the Hubble parameter can be alleviated.
The standard cosmological model, the flat CDM, based on general relativity theory plus a positive cosmological constant and dark matter, has been able to explain accurately the most diverse observations made in the past two decades.
Despite that, as new astronomical observations improve, in precision and in the diversity of cosmic tracers, arises a possible inability to explain within the standard paradigm quantitatively different measurements, and this is putting the CDM cosmology in a crossroads. The most notable issue is the current tension on the Hubble parameter H0 . Assuming the CDM scenario, Planck-CMB data analysis provides H0 = 67.4 ± 0.5 km s−1 Mpc−1 [1], while a modelindependent local measurement from Hubble Space Telescope observations of 70 long-period Cepheids in the Large Magellanic Cloud results H0 = 74.03 ± 1.42 km s−1 Mpc−1 [2]. These estimates are in 4.4 σ tension. Additionally, a combination of time-delay cosmography from H0LiCOW lenses and the distance ladder results is at 5.2 σ tension with CMB constraints [3]. Another accurate independent measure was carried out in [4], from Tip of the Red G
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