Publications
228 results found
Heavens AF, Seikel M, Nord BD, et al., 2014, Generalized Fisher matrices, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 445, Pages: 1687-1693, ISSN: 0035-8711
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- Citations: 10
Ade PAR, Aghanim N, Alves MIR, et al., 2014, Planck 2013 results. I. Overview of products and scientific results, Astronomy & Astrophysics, Vol: 571, ISSN: 1432-0746
The European Space Agency’s Planck satellite, dedicated to studying the early Universe and its subsequent evolution, was launched 14 May 2009 and has been scanning the microwave and submillimetre sky continuously since 12 August 2009. In March 2013, ESA and the Planck Collaboration released the initial cosmology products based on the first 15.5 months of Planck data, along with a set of scientific and technical papers and a web-based explanatory supplement. This paper gives an overview of the mission and its performance, the processing, analysis, and characteristics of the data, the scientific results, and the science data products and papers in the release. The science products include maps of the cosmic microwave background (CMB) and diffuse extragalactic foregrounds, a catalogue of compact Galactic and extragalactic sources, and a list of sources detected through the Sunyaev-Zeldovich effect. The likelihood code used to assess cosmological models against the Planck data and a lensing likelihood are described. Scientific results include robust support for the standard six-parameter ΛCDM model of cosmology and improved measurements of its parameters, including a highly significant deviation from scale invariance of the primordial power spectrum. The Planck values for these parameters and others derived from them are significantly different from those previously determined. Several large-scale anomalies in the temperature distribution of the CMB, first detected by WMAP, are confirmed with higher confidence. Planck sets new limits on the number and mass of neutrinos, and has measured gravitational lensing of CMB anisotropies at greater than 25σ. Planck finds no evidence for non-Gaussianity in the CMB. Planck’s results agree well with results from the measurements of baryon acoustic oscillations. Planck finds a lower Hubble constant than found in some more local measures. Some tension is also present between the amplitude of matter fluc
Ade PAR, Aghanim N, Armitage-Caplan C, et al., 2014, Planck 2013 results. XXIV. Constraints on primordial non-Gaussianity, Astronomy & Astrophysics, Vol: 571, ISSN: 1432-0746
The Planck nominal mission cosmic microwave background (CMB) maps yield unprecedented constraints on primordial non-Gaussianity (NG). Using three optimal bispectrum estimators, separable template-fitting (KSW), binned, and modal, we obtain consistent values for the primordial local, equilateral, and orthogonal bispectrum amplitudes, quoting as our final result fNLlocal = 2.7 ± 5.8, fNLequil = -42 ± 75, and fNLorth = -25 ± 39 (68% CL statistical). Non-Gaussianity is detected in the data; using skew-Cℓ statistics we find a nonzero bispectrum from residual point sources, and the integrated-Sachs-Wolfe-lensing bispectrum at a level expected in the ΛCDM scenario. The results are based on comprehensive cross-validation of these estimators on Gaussian and non-Gaussian simulations, are stable across component separation techniques, pass an extensive suite of tests, and are confirmed by skew-Cℓ, wavelet bispectrum and Minkowski functional estimators. Beyond estimates of individual shape amplitudes, we present model-independent, three-dimensional reconstructions of the Planck CMB bispectrum and thus derive constraints on early-Universe scenarios that generate primordial NG, including general single-field models of inflation, excited initial states (non-Bunch-Davies vacua), and directionally-dependent vector models. We provide an initial survey of scale-dependent feature and resonance models. These results bound both general single-field and multi-field model parameter ranges, such as the speed of sound, cs ≥ 0.02 (95% CL), in an effective field theory parametrization, and the curvaton decay fraction rD ≥ 0.15 (95% CL). The Planck data significantly limit the viable parameter space of the ekpyrotic/cyclic scenarios. The amplitude of the four-point function in the local model τNL< 2800 (95% CL). Taken together, these constraints represent the highest precision tests to date of physical mechanisms for the origin of cosmic structure.
Verde L, Jimenez R, Simpson F, et al., 2014, The bias of weighted dark matter haloes from peak theory, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 443, Pages: 122-137, ISSN: 0035-8711
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- Citations: 10
Munshi D, Corasaniti PS, Coles P, et al., 2014, Reionization and CMB non-Gaussianity, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 442, Pages: 3427-3442, ISSN: 0035-8711
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- Citations: 3
Kitching TD, Heavens AF, Alsing J, et al., 2014, 3D cosmic shear: cosmology from CFHTLenS, Monthly Notices of the Royal Astronomical Society, Vol: 442, Pages: 1326-1349, ISSN: 0035-8711
This paper presents the first application of 3D cosmic shear to a wide-field weak lensing survey. 3D cosmic shear is a technique that analyses weak lensing in three dimensions using a spherical harmonic approach, and does not bin data in the redshift direction. This is applied to CFHTLenS, a 154 square degree imaging survey with a median redshift of 0.7 and an effective number density of 11 galaxies per square arcminute usable for weak lensing. To account for survey masks we apply a 3D pseudo-Cℓ approach on weak lensing data, and to avoid uncertainties in the highly non-linear regime, we separately analyse radial wavenumbers k ≤ 1.5 and 5.0 h Mpc−1, and angular wavenumbers ℓ ≈ 400–5000. We show how one can recover 2D and tomographic power spectra from the full 3D cosmic shear power spectra and present a measurement of the 2D cosmic shear power spectrum, and measurements of a set of 2-bin and 6-bin cosmic shear tomographic power spectra; in doing so we find that using the 3D power in the calculation of such 2D and tomographic power spectra from data naturally accounts for a minimum scale in the matter power spectrum. We use 3D cosmic shear to constrain cosmologies with parameters ΩM, ΩB, σ8, h , ns, w0 and wa. For a non-evolving dark energy equation of state, and assuming a flat cosmology, lensing combined with Wilkinson Microwave Anisotropy Probe 7 results in h = 0.78 ± 0.12, ΩM = 0.252 ± 0.079, σ8 = 0.88 ± 0.23 and w = −1.16 ± 0.38 using only scales k ≤ 1.5 h Mpc−1. We also present results of lensing combined with first year Planck results, where we find no tension with the results from this analysis, but we also find no significant improvement over the Planck results alone. We find evidence of a suppression of power compared to Lambda cold dark matter (LCDM) on small scales 1.5 < k ≤ 5.0 h Mpc−1 in the l
Munshi D, Hu B, Renzi A, et al., 2014, Probing modified gravity theories with ISW and CMB lensing, Monthly Notices of the Royal Astronomical Society, Vol: 442, Pages: 821-837, ISSN: 1365-2966
We use the optimized skew-spectrum as well as the skew-spectra associated with the Minkowski functionals to test the possibility of using the cross-correlation of the integrated Sachs–Wolfe effect (ISW) and lensing of the cosmic microwave background (CMB) radiation to detect deviations in the theory of gravity away from General Relativity (GR). We find that the although both statistics can put constraints on modified gravity, the optimized skew-spectra are especially sensitive to the parameter B0 that denotes the Compton wavelength of the scalaron at the present epoch. We investigate three modified gravity theories, namely the post-parametrized Friedmann formalism; the Hu–Sawicki model and the Bertschinger–Zukin (BZ) formalism. Employing a likelihood analysis for an experimental setup similar to ESA's Planck mission, we find that, assuming GR to be the correct model, we expect the constraints from the first two skew-spectra, S(0)ℓSℓ(0) and S(1)ℓSℓ(1), to be the same: B0 < 0.45 at 95 per cent confidence level (CL) and B0 < 0.67 at 99 per cent CL in the BZ model. The third skew-spectrum does not give any meaningful constraint. We find that the optimal skew-spectrum provides much more powerful constraint, giving B0 < 0.071 at 95 per cent CL and B0 < 0.15 at 99 per cent CL, which is essentially identical to what can be achieved using the full bispectrum.
Duncan CAJ, Joachimi B, Heavens AF, et al., 2013, On the complementarity of galaxy clustering with cosmic shear and flux magnification, Monthly Notices of the Royal Astronomical Society, Vol: 437, Pages: 2471-2487, ISSN: 1365-2966
With the wealth of forthcoming data from wide-field surveys, it is more important than ever to understand the full range of independent probes of cosmology at our disposal. Here, we explore the potential for galaxy clustering and cosmic shear, separately and in combination, including the effects of lensing magnification. We show that inferred cosmological parameters may be biased when flux magnification is neglected. Results are presented for Stage III ground-based and Stage IV space-based photometric surveys, using slopes of the luminosity function inferred from the Canada–France–Hawaii Lensing Survey catalogue. We find that combining with clustering improves the shear Dark Energy Task Force-like Figure of Merit by a factor of 1.33 using only autocorrelations in redshift for the clustering analysis, rising to 1.52 when cross-correlations are also included. The further addition of galaxy–galaxy lensing gives increases in the shear Figure of Merit by a factor of 2.82 and 3.7 for each type of clustering analysis, respectively. The presence of flux magnification in a clustering analysis does not significantly affect the precision of cosmological constraints when combined with cosmic shear and galaxy–galaxy lensing. However, if magnification is neglected, inferred cosmological parameter values are biased, with biases in some cosmological parameters larger than statistical errors.
Simpson F, Heavens AF, Heymans C, 2013, Clipping the cosmos. II. Cosmological information from nonlinear scales, PHYSICAL REVIEW D, Vol: 88, ISSN: 1550-7998
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- Citations: 23
Munshi D, Smidt J, Cooray A, et al., 2013, New approaches to probing Minkowski functionals, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 434, Pages: 2830-2855, ISSN: 0035-8711
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- Citations: 15
Amendola L, Appleby S, Bacon D, et al., 2013, Cosmology and Fundamental Physics with the Euclid Satellite, Living Reviews in Relativity, Vol: 16, ISSN: 1433-8351
Euclid is a European Space Agency medium-class mission selected for launch in 2019 withinthe Cosmic Vision 2015 – 2025 program. The main goal of Euclid is to understand the originof the accelerated expansion of the universe. Euclid will explore the expansion history of theuniverse and the evolution of cosmic structures by measuring shapes and red-shifts of galaxiesas well as the distribution of clusters of galaxies over a large fraction of the sky.Although the main driver for Euclid is the nature of dark energy, Euclid science covers avast range of topics, from cosmology to galaxy evolution to planetary research. In this reviewwe focus on cosmology and fundamental physics, with a strong emphasis on science beyondthe current standard models. We discuss five broad topics: dark energy and modified gravity,dark matter, initial conditions, basic assumptions and questions of methodology in the dataanalysis.This review has been planned and carried out within Euclid’s Theory Working Group andis meant to provide a guide to the scientific themes that will underlie the activity of the groupduring the preparation of the Euclid mission.
Heymans C, Grocutt E, Heavens A, et al., 2013, CFHTLenS tomographic weak lensing cosmological parameter constraints: Mitigating the impact of intrinsic galaxy alignments, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 432, Pages: 2433-2453, ISSN: 0035-8711
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- Citations: 470
Verde L, Jimenez R, Alvarez-Gaume L, et al., 2013, Multi-variate joint PDF for non-Gaussianities: exact formulation and generic approximations, JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS, ISSN: 1475-7516
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- Citations: 8
Heavens A, Alsing J, Jaffe AH, 2013, Combining size and shape in weak lensing, Monthly Notices of the Royal Astronomical Society: Letters, Vol: 433, Pages: L6-L10, ISSN: 1745-3933
Weak lensing alters the size of images with a similar magnitude to the distortion due to shear. Galaxy size probes the convergence field and shapes the shear field, both of which contain cosmological information. We show the gains expected in the dark energy figure of merit if galaxy size information is used in combination with galaxy shape. In any normal analysis of cosmic shear, galaxy sizes are also studied, so this is extra statistical information that comes for free and is currently unused. There are two main results in this Letter: first, we show that size measurement can be made uncorrelated with ellipticity measurement, thus allowing the full statistical gain from the combination, provided that √area is used as a size indicator; secondly, as a proof of concept, we show that when the relevant modes are noise dominated, as is the norm for lensing surveys, the gains are substantial, with improvements of about 68 per cent in the figure of merit expected when systematic errors are ignored. An approximate treatment of such systematics such as intrinsic alignments and size–magnitude correlations, respectively, suggests that a much better improvement in the dark energy figure of merit of even a factor of ∼4 may be achieved.
Casaponsa B, Heavens AF, Kitching TD, et al., 2013, Size magnification as a complement to cosmic shear, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 430, Pages: 2844-2853, ISSN: 0035-8711
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- Citations: 19
Hoyle B, Tojeiro R, Jimenez R, et al., 2013, TESTING HOMOGENEITY WITH GALAXY STAR FORMATION HISTORIES, ASTROPHYSICAL JOURNAL LETTERS, Vol: 762, ISSN: 2041-8205
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- Citations: 15
Munshi D, Coles P, Heavens A, 2013, Secondary anisotropies in CMB, skew-spectra and Minkowski Functionals, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 428, Pages: 2628-2644, ISSN: 0035-8711
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- Citations: 7
Rhodes J, Dobke B, Booth J, et al., 2012, Space-quality data from balloon-borne telescopes: The <i>High Altitude Lensing Observatory</i> (HALO), ASTROPARTICLE PHYSICS, Vol: 38, Pages: 31-40, ISSN: 0927-6505
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- Citations: 11
Simpson F, James JB, Heavens AF, et al., 2011, Clipping the Cosmos: The Bias and Bispectrum of Large Scale Structure, PHYSICAL REVIEW LETTERS, Vol: 107, ISSN: 0031-9007
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- Citations: 37
Kitching TD, Simpson F, Heavens AF, et al., 2011, Model selection for modified gravity, PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, Vol: 369, Pages: 5090-5101, ISSN: 1364-503X
Munshi D, Kitching T, Heavens A, et al., 2011, Higher order statistics for three-dimensional shear and flexion, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 416, Pages: 1629-1653, ISSN: 0035-8711
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- Citations: 22
Kitching T, Amara A, Gill M, et al., 2011, GRAVITATIONAL LENSING ACCURACY TESTING 2010 (GREAT10) CHALLENGE HANDBOOK, ANNALS OF APPLIED STATISTICS, Vol: 5, Pages: 2231-2263, ISSN: 1932-6157
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- Citations: 33
Heavens AF, Jimenez R, Maartens R, 2011, Testing homogeneity with the fossil record of galaxies, JOURNAL OF COSMOLOGY AND ASTROPARTICLE PHYSICS, ISSN: 1475-7516
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- Citations: 22
Kiessling A, Taylor AN, Heavens AF, 2011, Simulating the effect of non-linear mode coupling in cosmological parameter estimation, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 416, Pages: 1045-1055, ISSN: 0035-8711
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- Citations: 15
Heavens AF, Joachimi B, 2011, Cosmic magnification: nulling intrinsic clustering, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 415, Pages: 1681-1690, ISSN: 0035-8711
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- Citations: 17
Camera S, Kitching TD, Heavens AF, et al., 2011, Measuring unified dark matter with 3D cosmic shear, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 415, Pages: 399-409, ISSN: 0035-8711
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- Citations: 20
Kiessling A, Heavens AF, Taylor AN, et al., 2011, SUNGLASS: a new weak-lensing simulation pipeline, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 414, Pages: 2235-2245, ISSN: 0035-8711
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- Citations: 35
Munshi D, Heavens A, Cooray A, et al., 2011, Secondary non-Gaussianity and cross-correlation analysis, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 414, Pages: 3173-3197, ISSN: 0035-8711
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- Citations: 22
Kitching TD, Heavens AF, Miller L, 2011, 3D photometric cosmic shear, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 413, Pages: 2923-2934, ISSN: 0035-8711
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- Citations: 47
Tojeiro R, Percival WJ, Heavens AF, et al., 2011, The stellar evolution of luminous red galaxies, and its dependence on colour, redshift, luminosity and modelling, MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Vol: 413, Pages: 434-460, ISSN: 0035-8711
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- Citations: 36
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