Search Publications
Testing chameleon gravity with the Coma cluster
Bacon, David; Nichol, Robert C.; Lombriser, Lucas +3 more
We propose a novel method to test the gravitational interactions in the outskirts of galaxy clusters. When gravity is modified, this is typically accompanied by the introduction of an additional scalar degree of freedom, which mediates an attractive fifth force. The presence of an extra gravitational coupling, however, is tightly constrained by lo…
The observational status of Galileon gravity after Planck
Baugh, Carlton M.; Barreira, Alexandre; Li, Baojiu +1 more
We use the latest CMB data from Planck, together with BAO measurements, to constrain the full parameter space of Galileon gravity. We constrain separately the three main branches of the theory known as the Cubic, Quartic and Quintic models, and find that all yield a very good fit to these data. Unlike in ΛCDM, the Galileon model constraints are co…
Detection of thermal SZ-CMB lensing cross-correlation in Planck nominal mission data
Spergel, David N.; Hill, J. Colin
The nominal mission maps from the Planck satellite contain a wealth of information about secondary anisotropies in the cosmic microwave background (CMB), including those induced by the thermal Sunyaev-Zel'dovich (tSZ) effect and gravitational lensing. As both the tSZ and CMB lensing signals trace the large-scale matter density field, the anisotrop…
Standard big bang nucleosynthesis and primordial CNO abundances after Planck
Uzan, Jean-Philippe; Coc, Alain; Vangioni, Elisabeth
Primordial or big bang nucleosynthesis (BBN) is one of the three historical strong evidences for the big bang model. The recent results by the Planck satellite mission have slightly changed the estimate of the baryonic density compared to the previous WMAP analysis. This article updates the BBN predictions for the light elements using the cosmolog…
Using the CMB angular power spectrum to study Dark Matter-photon interactions
Lesgourgues, Julien; Wilkinson, Ryan J.; Bœhm, C. {é. }line
In this paper, we explore the impact of Dark Matter-photon interactions on the CMB angular power spectrum. Using the one-year data release of the Planck satellite, we derive an upper bound on the Dark Matter-photon elastic scattering cross section of σDM-γ <= 8 × 10-31 (mDM/GeV) cm2 (68% CL) if the cr…
Wiggly whipped inflation
Starobinsky, Alexei A.; Hazra, Dhiraj Kumar; Smoot, George F. +1 more
Motivated by BICEP2 results on the CMB polarization B-mode which imply primordial gravitational waves are produced when the Universe has the expansion rate of about H ≈ 1014 GeV, and by deviations from a smooth power-law behavior for multipoles ℓ <50 in the CMB temperature anisotropy power spectrum found in the WMAP and Planck experi…
Planck constraints on monodromy inflation
Easther, Richard; Flauger, Raphael
We use data from the nominal Planck mission to constrain modulations in the primordial power spectrum associated with monodromy inflation. The largest improvement in fit relative to the unmodulated model has Δχ2 ≈ 10 and we find no evidence for a primordial signal, in contrast to a previous analysis of the WMAP9 dataset, for which Δχ
Testing coupled dark energy with large scale structure observation
Yang, Weiqiang; Xu, Lixin
The coupling between the dark components provides a new approach to mitigate the coincidence problem of cosmological standard model. In this paper, dark energy is treated as a fluid with a constant equation of state, whose coupling with dark matter is Q̄=3Hξxρ̄x. In the frame of dark energy, we derive the evolution equations fo…
Primordial power spectrum from Planck
Hazra, Dhiraj Kumar; Shafieloo, Arman; Souradeep, Tarun
Using modified Richardson-Lucy algorithm we reconstruct the primordial power spectrum (PPS) from Planck Cosmic Microwave Background (CMB) temperature anisotropy data. In our analysis we use different combinations of angular power spectra from Planck to reconstruct the shape of the primordial power spectrum and locate possible features. Performing …
Suppressing the impact of a high tensor-to-scalar ratio on the temperature anisotropies
Peloso, Marco; Contaldi, Carlo R.; Sorbo, Lorenzo
The BICEP2 collaboration has reported a strong B mode signal in the CMB polarization, which is well fit by a tensor-to-scalar ratio of r simeq 0.2. This is greater than the upper limit r < 0.11 obtained from the temperature anisotropies under the assumption of a constant scalar spectral index ns. This discrepancy can be reduced once …