Massive Neutrinos and Magnetic Fields in the Early Universe (2009)
Shaw, J. Richard, Lewis, Antony
Primordial magnetic fields and massive neutrinos can leave an interesting signal in the CMB temperature and polarization. We perform a systematic analysis of general perturbations in the...
Weak lensing of the CMB (2009)
Hanson, Duncan, Challinor, Anthony, Lewis, Antony
The cosmic microwave background (CMB) represents a unique source for the study of gravitational lensing. It is extended across the entire sky, partially polarized, located at the extreme distance of...
Results of the GREAT08 Challenge: An image analysis competition for cosmological lensing (2009)
Bridle, Sarah, Balan, Sreekumar T., Bethge, Matthias, Gentile, Marc, Harmeling, Stefan, Heymans, Catherine, ...
We present the results of the GREAT08 Challenge, a blind analysis challenge to infer weak gravitational lensing shear distortions from images. The primary goal was to stimulate new ideas by...
Estimators for CMB Statistical Anisotropy (2009)
We use quadratic maximum-likelihood (QML) estimators to constrain models with Gaussian but statistically anisotropic Cosmic Microwave Background (CMB) fluctuations, using CMB maps with realistic...
Properties and use of CMB power spectrum likelihoods (2009)
Hamimeche, Samira, Lewis, Antony
Fast robust methods for calculating likelihoods from CMB observations on small scales generally rely on approximations based on a set of power spectrum estimators and their covariances. We...
Galaxy shear estimation from stacked images (2009)
Statistics of the weak lensing of galaxies can be used to constrain cosmology if the galaxy shear can be estimated accurately. In general this requires accurate modelling of unlensed galaxy shapes...
Deuterium abundance in the most metal-poor damped Lyman alpha system: converging on Ωb,0h^2 (2008)
Pettini, Max, Zych, Berkeley J., Murphy, Michael T., Lewis, Antony, Steidel, Charles C.
The most metal-poor damped Lyα system known to date, at zabs= 2.61843 in the spectrum of the QSO Q0913+072, with an oxygen abundance of only ∼1/250 of the solar value, shows six well-resolved DI...
Crossing the Phantom Divide with Parameterized Post-Friedmann Dark Energy (2008)
Fang, Wenjuan, Hu, Wayne, Lewis, Antony
Dark energy models with a single scalar field cannot cross the equation of state divide set by a cosmological constant. More general models that allow crossing require additional degrees of freedom...
Non-linear Redshift-Space Power Spectra (2008)
Shaw, J. Richard, Lewis, Antony
Distances in cosmology are usually inferred from observed redshifts - an estimate that is dependent on the local peculiar motion - giving a distorted view of the three dimensional structure and...
Pettini, Max, Zych, Berkeley J., Murphy, Michael T., Lewis, Antony, Steidel, Charles C.
The most metal-poor DLA known to date, at z = 2.61843 in the spectrum of the QSO Q0913+072, with an oxygen abundance only about 1/250 of the solar value, shows six well resolved D I Lyman series...
Cosmological parameters from WMAP 5-year temperature maps (2008)
I calculate a hybrid cross-power spectrum estimator from the WMAP 5-year CMB temperature maps, discuss the goodness of fit, and then constrain cosmological parameters. The spectrum and results are...
Likelihood Analysis of CMB Temperature and Polarization Power Spectra (2008)
Hamimeche, Samira, Lewis, Antony
Microwave background temperature and polarization observations are a powerful way to constrain cosmological parameters if the likelihood function can be calculated accurately. The temperature and...
Linear effects of perturbed recombination (2007)
Perturbations in the ionization fraction after recombination affect the Compton cooling of density perturbations. Once the gas temperature starts to decouple from the CMB temperature, ionization...
Prospects for Constraining Neutrino Mass Using Planck and Lyman-Alpha Forest Data (2007)
Gratton, Steven, Lewis, Antony, Efstathiou, George
In this paper we investigate how well Planck and Lyman-Alpha forest data will be able to constrain the sum of the neutrino masses, and thus, in conjunction with flavour oscillation experiments, be...
The 21cm angular-power spectrum from the dark ages (2007)
Lewis, Antony, Challinor, Anthony
At redshifts z >~ 30 neutral hydrogen gas absorbs CMB radiation at the 21cm spin-flip frequency. In principle this is observable and a high-precision probe of cosmology. We calculate the...
The Cosmic Microwave Background and the Ionization History of the Universe (2006)
Lewis, Antony, Weller, Jochen, Battye, Richard
Details of how the primordial plasma recombined and how the universe later reionized are currently somewhat uncertain. This uncertainty can restrict the accuracy of cosmological parameter...
The Lyman-alpha forest and WMAP year three (2006)
Viel, Matteo, Haehnelt, Martin G., Lewis, Antony
A combined analysis of Cosmic Microwave Background (CMB) and Lyman-a forest data allows to constrain the matter power spectrum from small scales of about 1 Mpc/h all the way to the horizon scale. The...
Observational constraints and cosmological parameters (2006)
I discuss the extraction of cosmological parameter constraints from the recent WMAP 3-year data, both on its own and in combination with other data. The large degeneracies in the first year data can...
Weak Gravitational Lensing of the CMB (2006)
Lewis, Antony, Challinor, Anthony
Weak gravitational lensing has several important effects on the cosmic microwave background (CMB): it changes the CMB power spectra, induces non-Gaussianities, and generates a B-mode polarization...
Cluster Masses from CMB and Galaxy Weak Lensing (2005)
Gravitational lensing can be used to directly constrain the projected density profile of galaxy clusters. We discuss possible future constraints from lensing of the CMB temperature and polarization,...
Lensed CMB simulation and parameter estimation (2005)
Modelling of the weak lensing of the CMB will be crucial to obtain correct cosmological parameter constraints from forthcoming precision CMB anisotropy observations. The lensing affects the power...
Lensed CMB power spectra from all-sky correlation functions (2005)
Challinor, Anthony, Lewis, Antony
Weak lensing of the CMB changes the unlensed temperature anisotropy and polarization power spectra. Accounting for the lensing effect will be crucial to obtain accurate parameter constraints from...
CMB anisotropies from primordial inhomogeneous magnetic fields (2004)
Primordial inhomogeneous magnetic fields of the right strength can leave a signature on the CMB temperature anisotropy and polarization. Potentially observable contributions to polarization B-modes...
Observable primordial vector modes (2004)
Primordial vector modes describe vortical fluid perturbations in the early universe. A regular solution exists with constant non-zero radiation vorticities on super-horizon scales. Baryons are...
Cosmological parameters and the WMAP data (2003)
I discuss whether the standard cosmological models fit the WMAP data well enough to justify parameter estimation with standard assumptions. The observed quadrupole is low (but has significant...
Contaldi, Carlo R., Hoekstra, Henk, Lewis, Antony
We use Cosmic Microwave Background (CMB) observations together with the Red-sequence Cluster Survey (RCS) weak lensing results to derive constraints on a range of cosmological parameters. This...
Observational constraints on the curvaton model of inflation (2002)
Gordon, Christopher, Lewis, Antony
Simple curvaton models can generate a mixture of of correlated primordial adiabatic and isocurvature perturbations. The baryon and cold dark matter isocurvature modes differ only by an...
Cosmological parameters from CMB and other data: a Monte-Carlo approach (2002)
We present a fast Markov Chain Monte-Carlo exploration of cosmological parameter space. We perform a joint analysis of results from recent CMB experiments and provide parameter constraints, including...
Closed Universes from Cosmological Instantons (2001)
Gratton, Steven, Lewis, Antony, Turok, Neil
Current observational data is consistent with the universe being slightly closed. We investigate families of singular and non-singular closed instantons that could describe the beginning of a closed...
Detecting magnetic CMB polarization on an incomplete sky (2001)
Lewis, Antony, Challinor, Anthony, Turok, Neil
The full sky cosmic microwave background polarization field can be decomposed into `electric' and `magnetic' components. Working in harmonic space we construct magnetic variables that can be measured...
Analysis of CMB polarization on an incomplete sky (2001)
Lewis, Antony, Challinor, Anthony, Turok, Neil
The full sky cosmic microwave background polarization field can be decomposed into 'electric' and 'magnetic' components. Working in harmonic space we construct window functions that allow clean...
Efficient Computation of CMB anisotropies in closed FRW models (1999)
Lewis, Antony, Challinor, Anthony, Lasenby, Anthony
We implement the efficient line of sight method to calculate the anisotropy and polarization of the cosmic microwave background for scalar and tensor modes in almost-Friedmann-Robertson-Walker models...
Quadratic Lagrangians and Topology in Gauge Theory Gravity (1999)
Lewis, Antony, Doran, Chris, Lasenby, Anthony
We consider topological contributions to the action integral in a gauge theory formulation of gravity. Two topological invariants are found and are shown to arise from the scalar and pseudoscalar...
Elastic Potential Scattering of Electrons in the Spacetime Algebra (1997)
The Spacetime Algebra provides an elegant language for studying the Dirac equation. I show how cross-section calculations can be done following a method suggested by Hestenes. [7] The S-matrix is...
Opera e musica sacra 1630-1750 (1978)
Opera e musica sacra 1630-1750, A cura di Antony Lewis e N Fortune. . - Milano. NALUAF000464, Rizzoli. NAEDAF004331, 1978.