530 citations · 1.1k across the 27 of their papers we have counts for
27 papers
Structure formation in an anisotropic universe: Eulerian perturbation theory
Juan P. Beltrán Almeida, Josué Motoa-Manzano, Jorge Noreña +2
We present an effective Eulerian description, in the non-relativistic regime, of the growth of cosmological perturbations around a homogeneous but anisotropic Bianchi I spacetime b…
Anisotropic solid dark energy
J. Motoa-Manzano, J. Bayron Orjuela-Quintana, Thiago S. Pereira +1
In this paper, we study a triad of inhomogeneous scalar fields, known as "solid", as a source of homogeneous but anisotropic dark energy. By using a dynamical system approach, we f…
Optimal Boltzmann hierarchies with non-vanishing spatial curvature
Cyril Pitrou, Thiago S. Pereira, Julien Lesgourgues
Within cosmological perturbation theory, the cosmic microwave background anisotropies are usually computed from a Boltzmann hierarchy coupled to the perturbed Einstein equations. I…
Extended FLRW Models: dynamical cancellation of cosmological anisotropies
Mikjel Thorsrud, Ben D. Normann, Thiago S. Pereira
We investigate a corner of the Bianchi models that has not received much attention: "extended FLRW models" (eFLRW) defined as a cosmological model with underlying anisotropic Bianc…
Beyond scalar, vector and tensor harmonics in maximally symmetric three-dimensional spaces
Cyril Pitrou, Thiago S. Pereira
We present a comprehensive construction of scalar, vector and tensor harmonics on maximally symmetric three-dimensional spaces. Our formalism relies on the introduction of spin-wei…
Bianchi spacetimes as super-curvature modes around isotropic cosmologies
Thiago S. Pereira, Cyril Pitrou
A powerful result in theoretical cosmology states that a subset of anisotropic Bianchi models can be seen as the homogeneous limit of (standard) linear cosmological perturbations.…
CMB statistical isotropy confirmation at all scales using multipole vectors
Renan A. Oliveira, Thiago S. Pereira, Miguel Quartin
We present an efficient numerical code and conduct, for the first time, a null and model-independent CMB test of statistical isotropy using Multipole Vectors (MVs) at all scales. B…
Topology and the suppression of CMB large-angle correlations
Armando Bernui, Camila P. Novaes, Thiago S. Pereira +1
To date, no compelling evidence has been found that the universe has non-trivial spatial topology. Meanwhile, anomalies in the observed CMB temperature map, such as the lack of cor…
Direction and redshift drifts for general observers and their applications in cosmology
Oton H. Marcori, Cyril Pitrou, Jean-Philippe Uzan +1
High precision astrometry now enables to measure the time drift of astrophysical observables in real time, hence providing new ways to probe different cosmological models. This art…
Two-point Correlation Functions in Inhomogeneous and Anisotropic Cosmologies
Oton H. Marcori, Thiago S. Pereira
Two-point correlation functions are ubiquitous tools of modern cosmology, appearing in disparate topics ranging from cosmological inflation to late-time astrophysics. When the back…
Extending the LCDM model through shear-free anisotropies
Thiago S. Pereira, Davincy T. Pabon
If the spacetime metric has anisotropic spatial curvature, one can afford to expand the universe isotropically, provided that the energy-momentum tensor satisfy a certain con- stra…
Beyond CDM: Problems, solutions, and the road ahead
Philip Bull, Yashar Akrami, Julian Adamek +37
Despite its continued observational successes, there is a persistent (and growing) interest in extending cosmology beyond the standard model, CDM. This is motivated by a range o…
Isotropization of the universe during inflation
Thiago S. Pereira, Cyril Pitrou
A primordial inflationary phase allows one to erase any possible anisotropic expansion thanks to the cosmic no-hair theorem. If there is no global anisotropic stress, then the anis…
New Geometric Representations of the CMB 2pcf
Andre L. Froes, Thiago S. Pereira, Armando Bernui +1
When searching for deviations of statistical isotropy in CMB, a popular strategy is to write the two-point correlation function (2pcf) as the most general function of four spherica…
Cosmological Signatures of Anisotropic Spatial Curvature
Thiago S. Pereira, Guillermo A. Mena Marugán, Saulo Carneiro
If one is willing to give up the cherished hypothesis of spatial isotropy, many interesting cosmological models can be developed beyond the simple anisotropically expanding scenari…
Weak-lensing -modes as a probe of the isotropy of the universe
Thiago S. Pereira, Cyril Pitrou, Jean-Philippe Uzan
We compute the angular power spectrum of the -modes of the weak-lensing shear in a spatially anisotropic spacetime. We find that there must also exist off-diagonal correlations…
Weak-lensing by the large scale structure in a spatially anisotropic universe: theory and predictions
Cyril Pitrou, Thiago S. Pereira, Jean-Philippe Uzan
This article details the computation of the two-point correlators of the convergence, - and -modes of the cosmic shear induced by the weak-lensing by large scale structure as…
Thermodynamics of quantum photon spheres
M. C. Baldiotti, Walace S. Elias, C. Molina +1
Photon spheres, surfaces where massless particles are confined in closed orbits, are expected to be common astrophysical structures surrounding ultracompact objects. In this paper…
North-South non-Gaussian asymmetry in PLANCK CMB maps
A. Bernui, A. F. Oliveira, T. S. Pereira
We report the results of a statistical analysis performed with the four foreground-cleaned Planck maps by means of a suitably defined {\it local-variance} estimator. Our analysis s…
Inflationary Super-Hubble Waves and the Size of the Universe
Thiago S. Pereira, Luis Gustavo T. Silva
The effect of the scalar spectral index on inflationary super-Hubble waves is to amplify/damp large wavelengths according to whether the spectrum is red () or blue ($n_{s}…
Real Space Approach to CMB deboosting
Amanda Yoho, Craig J. Copi, Glenn D. Starkman +1
The effect of our Galaxy's motion through the Cosmic Microwave Background rest frame, which aberrates and Doppler shifts incoming photons measured by current CMB experiments, has b…
Inflationary Perturbations in Anisotropic, Shear-Free Universes
Thiago S. Pereira, Saulo Carneiro, Guillermo A. Mena Marugan
In this work, the linear and gauge-invariant theory of cosmological perturbations in a class of anisotropic and shear-free spacetimes is developed. After constructing an explicit s…
Weak lensing B-modes on all scales as a probe of local isotropy
Cyril Pitrou, Jean-Philippe Uzan, Thiago S. Pereira
This article derives a multipolar hierarchy for the propagation of the weak-lensing shear and convergence in a general spacetime. The origin of B-modes, in particular on large angu…
Effects of a Cut, Lorentz-Boosted sky on the Angular Power Spectrum
Thiago S. Pereira, Amanda Yoho, Maik Stuke +1
The largest fluctuation in the observed CMB temperature field is the dipole, its origin being usually attributed to the Doppler Effect - the Earth's velocity with respect to the CM…