Search Publications
Reconciling Planck with the local value of H0 in extended parameter space
Di Valentino, Eleonora; Melchiorri, Alessandro; Silk, Joseph
The recent determination of the local value of the Hubble constant by Riess et al., 2016 (hereafter R16) is now 3.3 sigma higher than the value derived from the most recent CMB anisotropy data provided by the Planck satellite in a ΛCDM model. Here we perform a combined analysis of the Planck and R16 results in an extended parameter space, varying …
Cosmological axion and neutrino mass constraints from Planck 2015 temperature and polarization data
Di Valentino, Eleonora; Melchiorri, Alessandro; Mena, Olga +3 more
Axions currently provide the most compelling solution to the strong CP problem. These particles may be copiously produced in the early universe, including via thermal processes. Therefore, relic axions constitute a hot dark matter component and their masses are strongly degenerate with those of the three active neutrinos, as they leave identical s…
New constraints on primordial gravitational waves from Planck 2015
Melchiorri, Alessandro; Pagano, Luca; Salvati, Laura
We show that the new precise measurements of Cosmic Microwave Background (CMB) temperature and polarization anisotropies made by the Planck satellite significantly improves previous constraints on the cosmic gravitational waves background (CGWB) at frequencies f >10-15 Hz. On scales smaller than the horizon at the time of decoupling,…
CMB constraint on dark matter annihilation after Planck 2015
Nakayama, Kazunori; Kawasaki, Masahiro; Sekiguchi, Toyokazu
We update the constraint on the dark matter annihilation cross section by using the recent measurements of the CMB anisotropy by the Planck satellite. We fully calculate the cascade of dark matter annihilation products and their effects on ionization, heating and excitation of the hydrogen, hence do not rely on any assumption on the energy fractio…
Galaxy clustering, CMB and supernova data constraints on ϕCDM model with massive neutrinos
Xu, Lixin; Chen, Yun
We investigate a scalar field dark energy model (i.e., ϕCDM model) with massive neutrinos, where the scalar field possesses an inverse power-law potential, i.e., V (ϕ) ∝ϕ-α (α > 0). We find that the sum of neutrino masses Σmν has significant impacts on the CMB temperature power spectrum and on the matter power spectrum. In…
Direct search for features in the primordial bispectrum
Appleby, Stephen; Hazra, Dhiraj Kumar; Gong, Jinn-Ouk +2 more
We study features in the bispectrum of the primordial curvature perturbation correlated with the reconstructed primordial power spectrum from the observed cosmic microwave background temperature data. We first show how the bispectrum can be completely specified in terms of the power spectrum and its first two derivatives, valid for any configurati…
Preferred axis of CMB parity asymmetry in the masked maps
Cheng, Cheng; Huang, Qing-Guo; Santos, Larissa +1 more
Both WMAP and Planck data show a significant odd-multipole preference in the large scales of the cosmic microwave background (CMB) temperature anisotropies. If this pattern originates from cosmological effects, then it can be considered a crucial clue for a violation in the cosmological principle. By defining various direction dependent statistics…
Running cosmological constant with observational tests
Geng, Chao-Qiang; Lee, Chung-Chi; Zhang, Kaituo
We investigate the running cosmological constant model with dark energy linearly proportional to the Hubble parameter, Λ = σH +Λ0, in which the ΛCDM limit is recovered by taking σ = 0. We derive the linear perturbation equations of gravity under the Friedmann-Lemaïtre-Robertson-Walker cosmology, and show the power spectra of the CMB tem…