Search Publications
Constraint on the primordial gravitational waves from the joint analysis of BICEP2 and Planck HFI 353 GHz dust polarization data
Cheng, Cheng; Huang, Qing-Guo; Wang, Sai
We make a joint analysis of BICEP2 and recently released Planck HFI 353 GHz dust polarization data, and find that there is no evidence for the primordial gravitational waves and the bound on the tensor-to-scalar ratio becomes r < 0.083 at 95% confidence level in the base ΛCDM + tensor model. Extending to the model with running of scalar spectra…
Suppressing CMB low multipoles with ISW effect
Das, Santanu; Souradeep, Tarun
Recent results of Planck data reveal that the power [1,2] in the low multipoles of the CMB angular power spectrum, approximately up to l = 30, is significantly lower than the theoretically predicted in the best fit ΛCDM model. There are different known physical effects that can affect the power at low multipoles, such as features in the primordial…
Isocurvature perturbations and tensor mode in light of Planck and BICEP2
Takahashi, Tomo; Kawasaki, Masahiro; Sekiguchi, Toyokazu +1 more
We investigate the degeneracy of the isocurvature perturbations and the primordial gravitational waves, by using recent observations of the cosmic microwave background (CMB) reported by Planck and BICEP2 collaborations. We show that the tension in the bound on the tensor-to-scalar ratio r between Planck and BICEP2 can be resolved by introducing th…
Cosmological evidence for leptonic asymmetry after Planck
Popa, L. A.; Caramete, A.
Recently, the PLANCK satellite found a larger and most precise value of the matter energy density, that impacts on the present values of other cosmological parameters such as the Hubble constant H0, the present cluster abundances S8, and the age of the Universe tU. The existing tension between PLANCK determination …
The traces of anisotropic dark energy in light of Planck
Kunz, Martin; Cardona, Wilmar; Hollenstein, Lukas
We study a dark energy model with non-zero anisotropic stress, either linked to the dark energy density or to the dark matter density. We compute approximate solutions that allow to characterise the behaviour of the dark energy model and to assess the stability of the perturbations. We also determine the current limits on such an anisotropic stres…
Confronting the concordance model of cosmology with Planck data
Hazra, Dhiraj Kumar; Shafieloo, Arman
We confront the concordance (standard) model of cosmology, the spatially flat ΛCDM Universe with power-law form of the primordial spectrum with Planck CMB angular power spectrum data searching for possible smooth deviations beyond the flexibility of the standard model. The departure from the concordance cosmology is modeled in the context of Cross…
Searching for primordial non-Gaussianity in Planck CMB maps using a combined estimator
Wuensche, C. A.; Novaes, C. P.; Bernui, A. +1 more
The extensive search for deviations from Gaussianity in cosmic microwave background radiation (CMB) data is very important due to the information about the very early moments of the universe encoded there. Recent analyses from Planck CMB data do not exclude the presence of non-Gaussianity of small amplitude, although they are consistent with the G…
Cosmological parameter estimation from CMB and X-ray cluster after Planck
Hu, Bin; Cai, Rong-Gen; Guo, Zong-Kuan +1 more
We investigate constraints on cosmological parameters in three 8-parameter models with the summed neutrino mass as a free parameter, by a joint analysis of CCCP X-ray cluster data, the newly released Planck CMB data as well as some external data sets including baryon acoustic oscillation measurements from the 6dFGS, SDSS DR7 and BOSS DR9 surveys, …
Radiative inflation and dark energy RIDEs again after BICEP2
Di Bari, Pasquale; King, Stephen F.; Luhn, Christoph +2 more
Following the ground-breaking measurement of the tensor-to-scalar ratio r=0.20+0.07-0.05 by the BICEP2 collaboration, we perform a statistical analysis of a model that combines Radiative Inflation with Dark Energy (RIDE) based on the M2|Φ|2 ln (|Φ|2/Λ2) potential and compare its pre…
Tracing the cosmic velocity field at z 0.1 from galaxy luminosities in the SDSS DR7
Nusser, Adi; Feix, Martin; Branchini, Enzo
Spatial modulations in the distribution of observed luminosities (computed using redshifts) of ~ 5× 105 galaxies from the SDSS Data Release 7, probe the cosmic peculiar velocity field out to z~ 0.1. Allowing for luminosity evolution, the r-band luminosity function, determined via a spline-based estimator, is well represented by a Schech…