O-V-S-Z and friends: Non-Gaussianity from inhomogeneous reionization (2009)
Khatri, Rishi, Wandelt, Benjamin D.
We calculate the cosmic microwave background (CMB) bispectrum due to inhomogeneous reionization. We calculate all the terms that can contribute to the bispectrum that are products of first order...
21 cm radiation: A new probe of fundamental physics (2009)
Khatri, Rishi, Wandelt, Benjamin D.
New low frequency radio telescopes currently being built open up the possibility of observing the 21-cm radiation before the Epoch of Reionization in the future, in particular at redshifts 200 > z >...
Elsner, Franz, Wandelt, Benjamin D.
We describe an algorithm to generate temperature and polarization maps of the cosmic microwave background (CMB) radiation containing non-Gaussianity of arbitrary local type. We apply an optimized...
Improved simulation of non-Gaussian temperature and polarization CMB maps (2009)
Elsner, Franz, Wandelt, Benjamin D.
We describe an algorithm to generate temperature and polarization maps of the cosmic microwave background radiation containing non-Gaussianity of arbitrary local type. We apply an optimized...
Precision cosmology with voids: definition, methods, dynamics (2009)
Lavaux, Guilhem, Wandelt, Benjamin D.
We develop a new cosmic void finding technique based on methods of Lagrangian orbit reconstruction. We propose to define voids as the source point of repulsion of the comoving motion of galaxies in...
Cosmic Cartography of the Large-Scale Structure with Sloan Digital Sky Survey Data Release 6 (2009)
Kitaura, Francisco S., Jasche, Jens, Li, Cheng, Ensslin, Torsten A., Metcalf, R. Benton, Wandelt, Benjamin D., ...
We present the largest Wiener reconstruction of the cosmic density field made to date. The reconstruction is based on the Sloan Digital Sky Survey data release 6 covering the northern Galactic cap....
Parameters and pitfalls in dark energy models with time varying equation of state (2009)
Biswas, Rahul, Wandelt, Benjamin D.
Are geometrical summaries of the CMB and LSS sufficient for estimating cosmological parameters? And how does our choice of a dark energy model impact the current constraints on standard cosmological...
A bit more on crinkles in the last scattering surface (2009)
Khatri, Rishi, Wandelt, Benjamin D.
Inhomogeneous recombination can give rise to perturbations in the electron number density which can be a factor of five larger than the perturbations in baryon density. We do a thorough analysis of...
Crinkles in the last scattering surface: Non-Gaussianity from inhomogeneous recombination (2008)
Khatri, Rishi, Wandelt, Benjamin D.
The perturbations in the electron number density during recombination contributes to the Cosmic Microwave Background bispectrum through second order terms. Perturbations in the electron density can...
PReBeaM for Planck: A Polarized Regularized Beam Deconvolution Map-Making Method (2008)
Armitage-Caplan, Charmaine, Wandelt, Benjamin D.
We describe a maximum likelihood regularized beam deconvolution map-making algorithm for data from high resolution, polarization sensitive instruments, such as the Planck data set. The resulting...
Cosmic (super)string constraints from 21 cm radiation (2008)
Khatri, Rishi, Wandelt, Benjamin D.
We calculate the contribution of cosmic strings arising from a phase transition in the early universe, or cosmic superstrings arising from brane inflation, to the cosmic 21 cm power spectrum at...
Yadav, Amit P. S., Wandelt, Benjamin D.
We present evidence for the detection of primordial non-Gaussianity of the local type (fNL), using the temperature information of the Cosmic Microwave Background (CMB) from the WMAP 3-year data. We...
Computing High Accuracy Power Spectra with Pico (2007)
Fendt, William A., Wandelt, Benjamin D.
This paper presents the second release of Pico (Parameters for the Impatient COsmologist). Pico is a general purpose machine learning code which we have applied to computing the CMB power spectra and...
Yadav, Amit P. S., Komatsu, Eiichiro, Wandelt, Benjamin D., Liguori, Michele, Hansen, Frode K., Matarrese, Sabino
In our recent paper (Yadav et al. 2007) we described a fast cubic (bispectrum) estimator of the amplitude of primordial non-Gaussianity of local type, f_{NL}, from a combined analysis of the Cosmic...
Donzelli, Simona, Maino, Davide, Bersanelli, Marco, Childers, Jeffrey, Figueiredo, Newton, Lubin, Philip M., ...
We present the angular power spectrum of the cosmic microwave background (CMB) component extracted with FastICA from the Background Emission Anisotropy Scanning Telescope (BEAST) data. BEAST is a...
Advanced Methods for Cosmic Microwave (2007)
Background Data Analysis, Benjamin D. Wandelt, To Order N
In this talk I propose the rst fast methods which can analyze CMB data taking into account correlated noise, arbitrary beam shapes, non-uniform distribution of integration time on the sky, and...
Yadav, Amit P. S., Komatsu, Eiichiro, Wandelt, Benjamin D.
Measurements of primordial non-Gaussianity ($f_{NL}$) open a new window onto the physics of inflation. We describe a fast cubic (bispectrum) estimator of $f_{NL}$, using a combined analysis of...
21 cm radiation - a new probe of variation in the fine structure constant (2007)
Khatri, Rishi, Wandelt, Benjamin D.
We investigate the effect of variation in the value of the fine structure constant at high redshifts (recombination > z > 30) on the absorption of the cosmic microwave background (CMB) at 21 cm...
Pico: Parameters for the Impatient Cosmologist (2006)
Fendt, William A., Wandelt, Benjamin D.
We present a fast, accurate, robust and flexible method of accelerating parameter estimation. This algorithm, called Pico, can compute the CMB power spectrum and matter transfer function as well as...
Optimal Image Reconstruction in Radio Interferometry (2006)
Sutton, Edmund C., Wandelt, Benjamin D.
We introduce a method for analyzing radio interferometry data which produces maps which are optimal in the Bayesian sense of maximum posterior probability density, given certain prior assumptions. It...
Larson, David L., Wandelt, Benjamin D.
We present a careful frequentist analysis of one- and two-point statistics of the hot and cold spots in the cosmic microwave background (CMB) data obtained by the Wilkinson Microwave Anisotropy Probe...
Deconvolution Map-Making for Cosmic Microwave Background Observations (2004)
Armitage, Charmaine, Wandelt, Benjamin D.
We describe a new map-making code for cosmic microwave background (CMB) observations. It implements fast algorithms for convolution and transpose convolution of two functions on the sphere (Wandelt &...
Lin, Yen-Ting, Wandelt, Benjamin D.
We present here a detailed, self--contained treatment of the mathematical formalism for describing the theory of polarized anisotropy in the cosmic microwave background. This didactic review is aimed...
Interacting Quintessence, Cosmic Acceleration and the Coincidence Problem (2004)
Huey, Greg, Wandelt, Benjamin D.
Faced by recent evidence for a flat universe dominated by dark energy, cosmologists grapple with deep cosmic enigmas such as the cosmological constant problem, extreme fine-tuning and the cosmic...
The Hot and Cold Spots in the WMAP Data are Not Hot and Cold Enough (2004)
Larson, David L., Wandelt, Benjamin D.
This paper presents a frequentist analysis of the hot and cold spots of the cosmic microwave background data collected by the Wilkinson Microwave Anisotropy Probe (WMAP). We compare the WMAP...
Statistical Challenges of Cosmic Microwave Background Analysis (2004)
The Cosmic Microwave Background (CMB) is an abundant source of cosmological information. However, this information is encoded in non-trivial ways in a signal that is difficult to observe. The...
In this talk I describe MAGIC, an efficient approach to covariance estimation and signal reconstruction for Gaussian random fields (MAGIC Allows Global Inference of Covariance). It solves a...
O'Dwyer, Ian J., Bersanelli, Marco, Childers, Jeffrey, Figueiredo, Newton, Halevi, Doron, Huey, Gregory G., ...
The Background Emission Anisotropy Scanning Telescope (BEAST) is a 2.2m off-axis telescope with an 8 element mixed Q (38-45GHz) and Ka (26-36GHz) band focal plane, designed for balloon borne and...
Global, Exact Cosmic Microwave Background Data Analysis Using Gibbs Sampling (2003)
Wandelt, Benjamin D., Larson, David L., Lakshminarayanan, Arun
We describe an efficient and exact method that enables global Bayesian analysis of cosmic microwave background (CMB) data. The method reveals the joint posterior density (or likelihood for flat...
Precision Primordial $^4$He Measurement with CMB Experiments (2003)
Huey, Greg, Cyburt, Richard H., Wandelt, Benjamin D.
Big bang nucleosynthesis (BBN) and the cosmic microwave background (CMB) are two major pillars of cosmology. Standard BBN accurately predicts the primordial light element abundances ($^4$He, D,...
Measuring primordial non-Gaussianity in the cosmic microwave background (2003)
Komatsu, Eiichiro, Spergel, David N., Wandelt, Benjamin D.
We derive a fast way for measuring primordial non-Gaussianity in a nearly full-sky map of the cosmic microwave background. We find a cubic combination of sky maps combining bispectrum configurations...
A Map of the Cosmic Microwave Background from the BEAST Experiment (2003)
Meinhold, Peter R., Bersanelli, Marco, Childers, Jeffrey, Figueiredo, Newton, Gaier, Todd C., Halevi, Doron, ...
We present the first sky maps from the BEAST (Background Emission Anisotropy Scanning Telescope) experiment. BEAST consists of a 2.2 meter off axis Gregorian telescope fed by a cryogenic millimeter...
Cyburt, Richard H., Fields, Brian D., Pavlidou, Vasiliki, Wandelt, Benjamin D.
Self-interacting dark matter (SIDM) was introduced by Spergel & Steinhardt to address possible discrepancies between collisionless dark matter simulations and observations on scales of less than 1...
Adaptive Ray Tracing for Radiative Transfer around Point Sources (2001)
Abel, Tom, Wandelt, Benjamin D.
We describe a novel adaptive ray tracing scheme to solve the equation of radiative transfer around point sources in hydrodynamical simulations. The angular resolution adapts to the local...
Measurement of the cosmic microwave background bispectrum on the COBE DMR sky maps (2001)
Komatsu, Eiichiro, Wandelt, Benjamin D., Spergel, David N., Banday, Anthony J., Gorski, Krzysztof M.
We measure the angular bispectrum of the cosmic microwave background (CMB) radiation anisotropy from the COBE Differential Microwave Radiometer (DMR) four-year sky maps. The angular bispectrum is the...
Fast, exact CMB power spectrum estimation for a certain class of observational strategies (2001)
Wandelt, Benjamin D., Hansen, Frode K.
We describe a class of observational strategies for probing the anisotropies in the cosmic microwave background (CMB) where the instrument scans on rings which can be combined into an n-torus, the...
In this talk I propose the first fast methods which can analyze CMB data taking into account correlated noise, arbitrary beam shapes, non-uniform distribution of integration time on the sky, and...
Fast Convolution on the Sphere (2000)
Wandelt, Benjamin D., Gorski, Krzysztof M.
We propose fast, exact and efficient algorithms for the convolution of two arbitrary functions on the sphere which speed up computations by a factor \order{\sqrt{N}} compared to present methods where...
Wandelt, Benjamin D., Hivon, Eric, Gorski, Krzysztof M.
As the era of high precision cosmology approaches, the empirically determined power spectrum of the microwave background anisotropy $C_l$ will provide a crucial test for cosmological theories. We...
Self-Interacting Dark Matter (2000)
Wandelt, Benjamin D., Dave, Romeel, Farrar, Glennys R., McGuire, Patrick C., Spergel, David N., Steinhardt, Paul J.
Spergel and Steinhardt have recently proposed the concept of dark matter with strong self-interactions as a means to address numerous discrepancies between observations of dark matter halos on...
Halo Properties in Cosmological Simulations of Self-Interacting Cold Dark Matter (2000)
Davé, Romeel, Spergel, David N., Steinhardt, Paul J., Wandelt, Benjamin D.
We present a comparison of halo properties in cosmological simulations of collisionless cold dark matter (CDM) and self-interacting dark matter (SIDM) for a range of dark matter cross sections. We...
Multiparameter estimation with the Pseudo-C_l method (2000)
Wandelt, Benjamin D., Gorski, Krzysztof M., Hivon, Eric
We apply the Pseudo-C_l formalism to obtain an unbiased, approximate method for efficient simultaneous estimation of several cosmological parameters from large, almost full-sky cosmic microwave...
Gorski, Krzysztof M., Wandelt, Benjamin D., Hansen, Frode K., Hivon, Eric, Banday, Anthony J.
HEALPix is a Hierarchical, Equal Area, and iso-Latitude Pixelisation of the sphere designed to support efficiently - local operations on the pixel set, - a hierarchical tree structure for...
CMB anisotropy power spectrum statistics (1998)
Wandelt, Benjamin D., Hivon, Eric, Gorski, Krzysztof M.
Much attention has been given to the problem of estimating cosmological parameters from the $C_l$ measured by future experiments. Many of the approaches which are being used either invoke poorly...
Cosmic microwave background anisotropy power spectrum statistics for high precision cosmology (1998)
Wandelt, Benjamin D., Hivon, Eric, Gorski, Krzysztof M.
As the era of high precision cosmology approaches, the empirically determined power spectrum of the microwave background anisotropy, $C_l$, will provide a crucial test for cosmological theories. We...
Topological Analysis of High-Resolution CMB Maps (1998)
Wandelt, Benjamin D., Hivon, Eric, Gorski, Kris M.
We report the development of numerical tools for the topological analysis of sub--degree resolution, all--sky maps. Software to be released in the HEALFAST (V0.9) package defines neighbour...
Primordial Non-Gaussianity: Baryon Bias and Gravitational Collapse of Cosmic String Wakes (1998)
I compute the 3-D non-linear evolution of gas and dark matter fluids in the neighbourhood of cosmic string wakes which are formed at high redshift ($z\simeq 2240$) for a ``realistic'' scenario of...
Satellite design parameters for detecting coherence in the microwave sky (1996)
Albrecht, Andreas, Wandelt, Benjamin D.
Recently it has been realized that observations of fluctuations in the cosmic microwave background (CMB) can reveal very interesting information about the degree of coherence exhibited by the...
Causality and the Power Spectrum (1995)
Robinson, James, Wandelt, Benjamin D.
We find constraints on the generation of super-causal-horizon energy perturbations from a smooth initial state, under a simple physical scheme. We quantify these constraints by placing the upper...