Classifying LISA gravitational wave burst signals using Bayesian evidence (2009)
Feroz, Farhan, Gair, Jonathan R., Graff, Philip, Hobson, Michael P, Lasenby, Anthony
We consider the problem of characterisation of burst sources detected with the Laser Interferometer Space Antenna (LISA) using the multi-modal nested sampling algorithm, MultiNest. We use MultiNest...
Bootstrapping gravity: a consistent approach to energy-momentum self-coupling (2009)
Butcher, Luke M., Hobson, Michael, Lasenby, Anthony
It is generally believed that coupling the graviton (a classical Fierz-Pauli massless spin-2 field) to its own energy-momentum tensor successfully recreates the dynamics of the Einstein field...
G64.5+0.9, a new shell supernova remnant with unusual central emission (2009)
Davies, Matthew L., Franzen, Thomas M. O., Grainge, Keith, Green, D. A., Hobson, Michael P., ...
We present observations between 1.4 and 18 GHz confirming that G64.5+0.9 is new Galactic shell supernova remnant, using the Very Large Array and the Arcminute Microkelvin Imager. The remnant is a...
AMI observations of northern supernova remnants at 14-18 GHz (2009)
Hurley-Walker, Natasha, Scaife, A. M. M., Green, D. A., Davies, Matthew L., Grainge, Keith, Hobson, Michael P., ...
We present observations between 14.2 and 17.9 GHz of 12 reported supernova remnants (SNRs) made with the Arcminute Microkelvin Imager Small Array (AMI SA). In conjunction with data from the...
The physical significance of the Babak-Grishchuk gravitational energy-momentum tensor (2008)
Butcher, Luke M., Lasenby, Anthony, Hobson, Michael
We examine the claim of Babak and Grishchuk [1] to have solved the problem of localising the energy and momentum of the gravitational field. After summarising Grishchuk's flat-space formulation of...
Recent Applications of Conformal Geometric Algebra (2008)
Abstract. We discuss a new covariant approach to geometry, called conformal geometric algebra, concentrating particularly on applications to projective geometry and new hybrid geometries. In...
Genova-Santos, Ricardo, Rubino-Martin, Jose Alberto, Rebolo, Rafael, Battye, Richard A., Blanco, Francisco, Davies, Rod D., ...
We present interferometric imaging at 33 GHz, with the new superextended configuration of the Very Small Array (VSA), of a very deep decrement in the cosmic microwave background (CMB) temperature....
Detection of a CMB decrement towards the (2007)
Quasar Pair Pc, Michael E. Jones, Richard Saunders, Joanne C. Baker, Garret Cotter, Alastair Edge, ...
In a 15-GHz Ryle-Telescope observation of PC1643+4631 A & B, a pair of quasars at redshifts z = 3:79 and 3.83 separated by 198 00 on the sky, we find a decrement in the cosmic microwave...
Detection of a CMB decrement towards the (2007)
Quasar Pair, Michael E. Jones, Richard Saunders, Joanne C. Baker, Garret Cotter, Alastair Edge, ...
In a 15-GHz Ryle-Telescope observation of PC1643+4631 A & B, a pair of quasars at redshifts z = 3:79 and 3.83 separated by 198 00 on the sky, we find a decrement in the cosmic microwave...
Scaife, Anna, Green, David A., Battye, Richard A., Davies, Rod D., Davis, Richard J., Dickinson, Clive, ...
We present results from observations made at 33 GHz with the Very Small Array (VSA) telescope towards potential candidates in the Galactic plane for spinning dust emission. In the cases of the...
Fermion scattering by a Schwarzschild black hole (2006)
Dolan, Sam, Doran, Chris, Lasenby, Anthony
We study the scattering of massive spin-half waves by a Schwarzschild black hole using analytical and numerical methods. We begin by extending a recent perturbation theory calculation to next order...
Events and cosmological spaces through twistors in the geometric (Clifford) algebra formalism (2006)
Arcaute, Elsa, Lasenby, Anthony, Doran, Chris
Events in Minkowski space-time can be obtained from the intersection of two twistors with no helicity. These can be represented within the geometric (Clifford) algebra formalism, in a particular...
Non-Gaussianity in the Very Small Array CMB maps with Smooth-Goodness-of-fit tests (2006)
Rubino-Martin, Jose Alberto, Aliaga, Antonio M., Barreiro, R. B., Battye, Richard A., Carreira, Pedro, Cleary, Kieran, ...
(Abridged) We have used the Rayner & Best (1989) smooth tests of goodness-of-fit to study the Gaussianity of the Very Small Array (VSA) data. Out of the 41 published VSA individual pointings...
A representation of twistors within geometric (Clifford) algebra (2006)
Arcaute, Elsa, Lasenby, Anthony, Doran, Chris
In previous work by two of the present authors, twistors were re-interpreted as 4-d spinors with a position dependence within the formalism of geometric (Clifford) algebra. Here we extend that...
Fermion absorption cross section of a Schwarzschild black hole (2005)
Doran, Chris, Lasenby, Anthony, Dolan, Sam, Hinder, Ian
We study the absorption of massive spin-half particles by a small Schwarzschild black hole by numerically solving the single-particle Dirac equation in Painleve-Gullstrand coordinates. We calculate...
Conformal models of de Sitter space, initial conditions for inflation and the CMB (2004)
Lasenby, Anthony, Doran, Chris
Conformal embedding of closed-universe models in a de Sitter background suggests a quantisation condition on the available conformal time. This condition implies that the universe is closed at no...
Cosmological parameter estimation with large scale structure and supernovae data (2004)
Odman, Carolina, Hobson, Mike, Lasenby, Anthony, Melchiorri, Alessandro
Most cosmological parameter estimations are based on the same set of observations and are therefore not independent. Here, we test the consistency of parameter estimations using a combination of...
Gravity, Gauge Theories and Geometric Algebra (2004)
Lasenby, Anthony, Doran, Chris, Gull, Stephen
A new gauge theory of gravity is presented. The theory is constructed in a flat background spacetime and employs gauge fields to ensure that all relations between physical quantities are independent...
Integral equations, Kerr-Schild fields and gravitational sources (2004)
Doran, Chris, Lasenby, Anthony
Kerr-Schild solutions to the vacuum Einstein equations are considered from the viewpoint of integral equations. We show that, for a class of Kerr-Schild fields, the stress-energy tensor can be...
High sensitivity measurements of the CMB power spectrum with the extended Very Small Array (2004)
Dickinson, Clive, Battye, Richard A., Cleary, Kieran, Davies, Rod D., Davis, Richard J., Genova-Santos, Ricardo, ...
We present deep Ka-band ($\nu \approx 33$ GHz) observations of the CMB made with the extended Very Small Array (VSA). This configuration produces a naturally weighted synthesized FWHM beamwidth of...
Cosmological parameter estimation using Very Small Array data out to l=1500 (2004)
Rebolo, Rafael, Battye, Richard A., Carreira, Pedro, Cleary, Kieran, Davies, Rod D., Davis, Richard J., ...
We estimate cosmological parameters using data obtained by the Very Small Array (VSA) in its extended configuration, in conjunction with a variety of other CMB data and external priors. Within the...
Estimating the bispectrum of the Very Small Array data (2004)
Smith, Sarah, Rocha, Graca, Challinor, Anthony, Battye, Richard A., Carreira, Pedro, Cleary, Kieran, ...
We estimate the bispectrum of the Very Small Array data from the compact and extended configuration observations released in December 2002, and compare our results to those obtained from Gaussian...
Cosmological parameter estimation using Very Small Array data out to l? = 1500 (2004)
Rebolo, Rafael, Battye, Richard A., Carreira, Pedro, Cleary, Kieran, Davies, Rod D., Davis, Richard J., ...
Searching for non-Gaussianity in the VSA data (2003)
Savage, Richard, Battye, Richard A., Carreira, Pedro, Cleary, Kieran, Davies, Rod D., Davis, Richard J., ...
We have tested Very Small Array (VSA) observations of three regions of sky for the presence of non-Gaussianity, using high-order cumulants, Minkowski functionals, a wavelet-based test and a Bayesian...
Closed Universes, de Sitter Space and Inflation (2003)
Lasenby, Anthony, Doran, Chris
We present a new approach to constructing inflationary models in closed universes. Conformal embedding of closed-universe models in a de Sitter background suggests a quantisation condition on the...
The CMB power spectrum out to l=1400 measured by the VSA (2002)
Grainge, Keith, Carreira, Pedro, Cleary, Kieran, Davies, Rod D., Davis, Richard J., Dickinson, Clive, ...
We have observed the cosmic microwave background (CMB) in three regions of sky using the Very Small Array (VSA) in an extended configuration with antennas of beamwidth 2 degrees at 34 GHz. Combined...
Cosmological parameter estimation and Bayesian model comparison using VSA data (2002)
Slosar, Anze, Carreira, Pedro, Cleary, Kieran, Davies, Rod D., Davis, Richard J., Dickinson, Clive, ...
We constrain the basic comological parameters using the first observations by the Very Small Array (VSA) in its extended configuration, together with existing cosmic microwave background data and...
New Techniques for Analysing Axisymmetric Gravitational Systems. 1. Vacuum Fields (2002)
Doran, Chris, Lasenby, Anthony
A new framework for analysing the gravitational fields in a stationary, axisymmetric configuration is introduced. The method is used to construct a complete set of field equations for the vacuum...
Bound states and decay times of fermions in a Schwarzschild black hole background (2002)
Lasenby, Anthony, Doran, Chris, Pritchard, Jonathan, Caceres, Alejandro, Dolan, Sam
We compute the spectrum of normalizable fermion bound states in a Schwarzschild black hole background. The eigenstates have complex energies. The real part of the energies, for small couplings,...
Braneworld Tensor Anisotropies in the CMB (2002)
Leong, Bernard, Challinor, Anthony, Maartens, Roy, Lasenby, Anthony
Cosmic microwave background (CMB) observations provide in principle a high-precision test of models which are motivated by M theory. We set out the framework of a program to compute the tensor...
First results from the Very Small Array -- IV. Cosmological parameter estimation (2002)
Rubino-Martin, Jose Alberto, Rebolo, Rafael, Carreira, Pedro, Cleary, Kieran, Davies, Rod D., Davis, Richard J., ...
We investigate the constraints on basic cosmological parameters set by the first compact-configuration observations of the Very Small Array (VSA), and other cosmological data sets, in the standard...
First results from the Very Small Array -- I. Observational methods (2002)
Watson, Robert A., Carreira, Pedro, Cleary, Kieran, Davies, Rod D., Davis, Richard J., Dickinson, Clive, ...
The Very Small Array (VSA) is a synthesis telescope designed to image faint structures in the cosmic microwave background on degree and sub-degree angular scales. The VSA has key differences from...
First results from the Very Small Array -- III. The CMB power spectrum (2002)
Scott, Paul F., Carreira, Pedro, Cleary, Kieran, Davies, Rod D., Davis, Richard, Dickinson, Clive, ...
We present the power spectrum of the fluctuations in the cosmic microwave background detected by the Very Small Array (VSA) in its first season of observations in its compact configuration. We find...
First results from the Very Small Array -- II. Observations of the CMB (2002)
Taylor, Angela C., Carreira, Pedro, Cleary, Kieran, Davies, Rod D., Davis, Richard J., Dickinson, Clive, ...
We have observed the cosmic microwave background temperature fluctuations in eight fields covering three separated areas of sky with the Very Small Array at 34 GHz. A total area of 101 square degrees...
Conformal Geometry, Euclidean Space and Geometric Algebra (2002)
Doran, Chris, Lasenby, Anthony, Lasenby, Joan
Projective geometry provides the preferred framework for most implementations of Euclidean space in graphics applications. Translations and rotations are both linear transformations in projective...
(1+3) Covariant Dynamics of Scalar Perturbations in Braneworlds (2001)
Leong, Bernard, Dunsby, Peter, Challinor, Anthony, Lasenby, Anthony
We discuss the dynamics of linear, scalar perturbations in an almost Friedmann-Robertson-Walker braneworld cosmology of Randall-Sundrum type II using the 1+3 covariant approach. We derive a complete...
Perturbation Theory Calculation of the Black Hole Elastic Scattering Cross Section (2001)
Doran, Chris, Lasenby, Anthony
The differential cross section for scattering of a Dirac particle in a black hole background is found. The result is the gravitational analog of the Mott formula for scattering in a Coulomb...
Bayesian joint estimation of non-Gaussianity and the power spectrum (2000)
Rocha, Graca, Magueijo, Joao, Hobson, Mike, Lasenby, Anthony
We propose a rigorous, non-perturbative, Bayesian framework which enables one jointly to test Gaussianity and estimate the power spectrum of CMB anisotropies. It makes use of the Hilbert space of an...
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...
Challinor, Anthony, Ford, Matthew, Lasenby, Anthony
We derive analytic expressions for the leading-order corrections to the polarization induced in the cosmic microwave background (CMB) due to scattering off hot electrons in galaxy clusters along the...
Comptonization of an isotropic distribution in moving media: higher-order effects (1998)
Challinor, Anthony, Lasenby, Anthony
We consider the Comptonization of an isotropic radiation field by a thermal distribution of electrons with non-vanishing bulk velocity. We include all relativistic effects, including induced...
Challinor, Anthony, Lasenby, Anthony
We present a fully covariant and gauge-invariant calculation of the evolution of anisotropies in the cosmic microwave background (CMB) radiation. We use the physically appealing covariant approach to...
Detection of a CMB decrement towards the z = 3.8 quasar pair PC1643+4631A&B (1996)
Jones, Michael E., Saunders, Richard, Baker, Joanne C., Cotter, Garret, Edge, Alastair, Grainge, Keith, ...
In a 15-GHz Ryle-Telescope observation of PC1643+4631 A & B, a pair of quasars at redshifts z = 3.79 and 3.83 separated by 198 arcsec on the sky, we find a decrement in the cosmic microwave...