Search Publications
Constraining models of f(R) gravity with Planck and WiggleZ power spectrum data
Hu, Bin; Dossett, Jason; Parkinson, David
In order to explain cosmic acceleration without invoking ``dark'' physics, we consider f(R) modified gravity models, which replace the standard Einstein-Hilbert action in General Relativity with a higher derivative theory. We use data from the WiggleZ Dark Energy survey to probe the formation of structure on large scales which can place tight cons…
Light sterile neutrinos after BICEP-2
Gariazzo, Stefano; Archidiacono, Maria; Fornengo, Nicolao +3 more
The recent discovery of B-modes in the polarization pattern of the Cosmic Microwave Background by the BICEP2 experiment has important implications for neutrino physics. We revisit cosmological bounds on light sterile neutrinos and show that they are compatible with all current cosmological data provided that the mass is relatively low. Using CMB d…
The Knotted Sky II: does BICEP2 require a nontrivial primordial power spectrum?
Aslanyan, Grigor; Easther, Richard; Price, Layne C. +1 more
An inflationary gravitational wave background consistent with BICEP2 is difficult to reconcile with a simple power-law spectrum of primordial scalar perturbations. Tensor modes contribute to the temperature anisotropies at multipoles with l≲ 100, and this effect - together with a prior on the form of the scalar perturbations - was the source of pr…
Neutrinos and dark energy after Planck and BICEP2: data consistency tests and cosmological parameter constraints
Zhang, Jing-Fei; Zhang, Xin; Geng, Jia-Jia
The detection of the B-mode polarization of the cosmic microwave background (CMB) by the BICEP2 experiment implies that the tensor-to-scalar ratio r should be involved in the base standard cosmology. In this paper, we extend the ΛCDM r+neutrino/dark radiation models by replacing the cosmological constant with the dynamical dark energy with constan…
Self-unitarization of New Higgs Inflation and compatibility with Planck and BICEP2 data
Germani, Cristiano; Watanabe, Yuki; Wintergerst, Nico
In this paper we show that the Germani-Kehagias model of Higgs inflation (or New Higgs Inflation), where the Higgs boson is kinetically non-minimally coupled to the Einstein tensor is in perfect compatibility with the latest Planck and BICEP2 data. Moreover, we show that the tension between the Planck and BICEP2 data can be relieved within the New…
Ruling out the power-law form of the scalar primordial spectrum
Starobinsky, Alexei A.; Hazra, Dhiraj Kumar; Smoot, George F. +1 more
Combining Planck CMB temperature [1] and BICEP2 B-mode polarization data [2,3] we show qualitatively that, assuming inflationary consistency relation, the power-law form of the scalar primordial spectrum is ruled out at more than 3σ CL. This is an important finding, since the power-law form of the scalar primordial spectrum is one of the main assu…
Signatures of anisotropic sources in the trispectrum of the cosmic microwave background
Shiraishi, Maresuke; Komatsu, Eiichiro; Peloso, Marco
Soft limits of N-point correlation functions, in which one wavenumber is much smaller than the others, play a special role in constraining the physics of inflation. Anisotropic sources such as a vector field during inflation generate distinct angular dependence in all these correlators, and introduce a fix privileged direction in our sky. In this …
Neutrino constraints: what large-scale structure and CMB data are telling us?
Viel, Matteo; Sartoris, Barbara; Costanzi, Matteo +1 more
We discuss the reliability of neutrino mass constraints, either active or sterile, from the combination of different low redshift Universe probes with measurements of CMB anisotropies. In our analyses we consider WMAP 9-year or Planck Cosmic Microwave Background (CMB) data in combination with Baryonic Acoustic Oscillations (BAO) measurements from …
Planck CMB anomalies: astrophysical and cosmological secondary effects and the curse of masking
Starck, J. -L.; Sureau, F.; Bobin, J. +2 more
Large-scale anomalies have been reported in CMB data with both WMAP and Planck data. These could be due to foreground residuals and or systematic effects, though their confirmation with Planck data suggests they are not due to a problem in the WMAP or Planck pipelines. If these anomalies are in fact primordial, then understanding their origin is f…
On the local variation of the Hubble constant
Hannestad, Steen; Odderskov, Io; Haugbølle, Troels
We have carefully studied how local measurements of the Hubble constant, H0, can be influenced by a variety of different parameters related to survey depth, size, and fraction of the sky observed, as well as observer position in space. Our study is based on N-body simulations of structure in the standard ΛCDM model and our conclusion is…