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6.0
Jun 30, 2018
06/18
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T. D. Kitching; A. F. Heavens; J. Alsing; T. Erben; C. Heymans; H. Hildebrandt; H. Hoekstra; A. Jaffe; A. Kiessling; Y. Mellier; L. Miller; L. van Waerbeke; J. Benjamin; J. Coupon; L. Fu; M. J. Hudson; M. Kilbinger; K. Kuijken; B. T. P. Rowe; T. Schrabback; E. Semboloni; M. Velander
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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...
Topics: Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1401.6842
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145
Jul 20, 2013
07/13
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T. D. Kitching; A. F. Heavens; L. Miller
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Here we present a number of improvements to weak lensing 3D power spectrum analysis, 3D cosmic shear, that uses the shape and redshift information of every galaxy to constrain cosmological parameters. We show how photometric redshift probability distributions for individual galaxies can be directly included in this statistic with no averaging. We also include the Limber approximation, considerably simplifying full 3D cosmic shear analysis, and we investigate its range of applicability. Finally...
Source: http://arxiv.org/abs/1007.2953v2
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Jun 30, 2018
06/18
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T. D. Kitching; A. F. Heavens; S. Das
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In this paper we present a power spectrum formalism that combines the full three-dimensional information from the galaxy ellipticity field, with information from the cosmic microwave background (CMB). We include in this approach galaxy cosmic shear and galaxy intrinsic alignments, CMB deflection, CMB temperature and CMB polarisation data; including the inter-datum power spectra between all quantities. We apply this to forecasting cosmological parameter errors for CMB and imaging surveys for...
Topics: Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1408.7052
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Sep 22, 2013
09/13
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A. F. Heavens; A. N. Taylor
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We re-examine the effects of redshift space distortion in all-sky galaxy redshift surveys in the formalism of spherical harmonics. Within this framework we show how one can treat both the large-scale linear effects, and the small-scale nonlinear clustering, exactly to first order. The method also allows in principle a determination of the power spectrum of perturbations, requiring no assumptions beyond that of linear theory. The method therefore offers significant advantages over Fourier...
Source: http://arxiv.org/abs/astro-ph/9409027v1
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Sep 17, 2013
09/13
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A. N. Taylor; W. E. Ballinger; A. F. Heavens; H. Tadros
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We apply a spherical harmonic analysis to the Point Source Redshift Survey (PSCz), to compute the real-space galaxy power spectrum and the degree of redshift distortion caused by peculiar velocities. We employ new parameter eigenvector and hierarchical data compression techniques, allowing a much larger number of harmonic modes to be included, and correspondingly smaller error bars. Using 4644 harmonic modes, compressed to 2278, we find that the IRAS redshift-space distortion parameter is...
Source: http://arxiv.org/abs/astro-ph/0007048v1
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Sep 19, 2013
09/13
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L. Miller; T. D. Kitching; C. Heymans; A. F. Heavens; L. Van Waerbeke
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The principles of measuring the shapes of galaxies by a model-fitting approach are discussed in the context of shape-measurement for surveys of weak gravitational lensing. It is argued that such an approach should be optimal, allowing measurement with maximal signal-to-noise, coupled with estimation of measurement errors. The distinction between likelihood-based and Bayesian methods is discussed. Systematic biases in the Bayesian method may be evaluated as part of the fitting process, and...
Source: http://arxiv.org/abs/0708.2340v1
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Sep 20, 2013
09/13
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T. D. Kitching; L. Miller; C. E. Heymans; L. van Waerbeke; A. F. Heavens
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We extend the Bayesian model fitting shape measurement method presented in Miller et al. (2007) and use the method to estimate the shear from the Shear TEsting Programme simulations (STEP). The method uses a fast model fitting algorithm which uses realistic galaxy profiles and analytically marginalises over the position and amplitude of the model by doing the model fitting in Fourier space. This is used to find the full posterior probability in ellipticity so that the shear can be estimated in...
Source: http://arxiv.org/abs/0802.1528v1
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Sep 19, 2013
09/13
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T. D. Kitching; A. F. Heavens; A. N. Taylor; M. L. Brown; K. Meisenheimer; C. Wolf; M. E. Gray; D. J. Bacon
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eye 50
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We present the first application of the 3D cosmic shear method developed in Heavens et al. (2006) and the geometric shear-ratio analysis developed in Taylor et al. (2006), to the COMBO-17 data set. 3D cosmic shear has been used to analyse galaxies with redshift estimates from two random COMBO-17 fields covering 0.52 square degrees in total, providing a conditional constraint in the (sigma_8, Omega_m) plane as well as a conditional constraint on the equation of state of dark energy,...
Source: http://arxiv.org/abs/astro-ph/0610284v2
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Sep 19, 2013
09/13
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Raul Jimenez; A. F. Heavens; M. R. S. Hawkins; P. Padoan
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Gravitational lensing studies suggest that the Universe may contain a population of dark galaxies; we investigate this intriguing possibility and propose a mechanism to explain their nature. In this mechanism a dark galaxy is formed with a low density disk in a dark halo of high spin parameter; such galaxies can have surface densities below the critical Toomre value for instabilities to develop, and following Kennicutt's work we expect these galaxies to have low star formation rates. The only...
Source: http://arxiv.org/abs/astro-ph/9709050v1
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Sep 21, 2013
09/13
by
A. F. Heavens; A. N. Taylor
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In this paper we consider methods of analysis and optimal design of redshift surveys. In the first part, we develop a formalism for analysing galaxy redshift surveys which are essentially two-dimensional, such as thin declination slices. The formalism is a power spectrum method, using spherical coordinates, allowing the distorting effects of galaxy peculiar velocities to be calculated to linear order on the assumption of statistical isotropy but without further approximation. In this paper, we...
Source: http://arxiv.org/abs/astro-ph/9705215v1
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Sep 19, 2013
09/13
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A. F. Heavens
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The bispectrum of the microwave background sky is a possible discriminator between inflationary and defect models of structure formation in the Universe. The bispectrum, which is the analogue of the temperature 3-point correlation function in harmonic space, is zero for most inflationary models, but non-zero for non-gaussian models. The expected departures from zero are small, and easily masked by noise, so it is important to be able to estimate the bispectrum coefficients as accurately as...
Source: http://arxiv.org/abs/astro-ph/9804222v1
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Sep 23, 2013
09/13
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T. D. Kitching; A. F. Heavens; L. Verde; P. Serra; A. Melchiorri
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In this paper we investigate the potential of 3D cosmic shear to constrain massive neutrino parameters. We find that if the total mass is substantial (near the upper limits from LSS, but setting aside the Ly alpha limit for now), then 3D cosmic shear + Planck is very sensitive to neutrino mass and one may expect that a next generation photometric redshift survey could constrain the number of neutrinos N_nu and the sum of their masses m_nu to an accuracy of dN_nu ~ 0.08 and dm_nu ~ 0.03 eV...
Source: http://arxiv.org/abs/0801.4565v1
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Sep 21, 2013
09/13
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A. F. Heavens
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eye 61
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This paper analyses the effects of random noise in determining errors and confidence levels for galaxy redshifts obtained by cross-correlation techniques. The main finding is that confidence levels have previously been overestimated, and errors inaccurately calculated in certain applications. New formul\ae\ are presented.
Source: http://arxiv.org/abs/astro-ph/9305031v2
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6.0
Jun 30, 2018
06/18
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A. F. Heavens; M. Seikel; B. D. Nord; M. Aich; Y. Bouffanais; B. A. Bassett; M. P. Hobson
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eye 6
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The Fisher Information Matrix formalism is extended to cases where the data is divided into two parts (X,Y), where the expectation value of Y depends on X according to some theoretical model, and X and Y both have errors with arbitrary covariance. In the simplest case, (X,Y) represent data pairs of abscissa and ordinate, in which case the analysis deals with the case of data pairs with errors in both coordinates, but X can be any measured quantities on which Y depends. The analysis applies for...
Topics: Methodology, Astrophysics, Statistics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1404.2854
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43
Sep 23, 2013
09/13
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A. F. Heavens
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eye 43
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Gravitational lensing causes background galaxy images to become aligned, and the statistical characteristics of the image alignments can then be used to constrain the power spectrum of mass fluctuations. Analyses of gravitational lensing assume that intrinsic galaxy alignments are negligible, but if this assumption does not hold, then the interpretation of image alignments will be in error. As gravitational lensing experiments become more ambitious and seek very low-level alignments arising...
Source: http://arxiv.org/abs/astro-ph/0109063v1
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46
Sep 18, 2013
09/13
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F. Calura; R. Jimenez; B. Panter; F. Matteucci; A. F. Heavens
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eye 46
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Using the star formation rates from the SDSS galaxy sample, extracted using the MOPED algorithm, and the empirical Kennicutt law relating star formation rate to gas density, we calculate the time evolution of the gas fraction as a function of the present stellar mass. We show how the gas-to-stars ratio varies with stellar mass, finding good agreement with previous results for smaller samples at the present epoch. For the first time we show clear evidence for progressive gas loss with cosmic...
Source: http://arxiv.org/abs/0707.1345v3
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51
Sep 18, 2013
09/13
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A. F. Heavens; T. D. Kitching; A. N. Taylor
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We present parameter estimation forecasts for present and future 3D cosmic shear surveys. We demonstrate that, in conjunction with results from cosmic microwave background (CMB) experiments, the properties of dark energy can be estimated with very high precision with large-scale, fully 3D weak lensing surveys. In particular, a 5-band, 10,000 square degree ground-based survey to a median redshift of zm=0.7 could achieve 1-$\sigma$ marginal statistical errors, in combination with the constraints...
Source: http://arxiv.org/abs/astro-ph/0606568v2
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50
Sep 18, 2013
09/13
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W. E. Ballinger; J. A. Peacock; A. F. Heavens
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eye 50
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It has been proposed that the cosmological constant $\Lambda$ might be measured from geometric effects on large-scale structure. A positive vacuum density leads to correlation-function contours which are squashed in the radial direction when calculated assuming a matter-dominated model. We show that this effect will be somewhat harder to detect than previous calculations have suggested: the squashing factor is likely to be $
Source: http://arxiv.org/abs/astro-ph/9605017v1
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Sep 24, 2013
09/13
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S. Gupta; A. Berera; A. F. Heavens; S. Matarrese
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eye 48
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We calculate the bispectrum of the gravitational field fluctuations generated during warm inflation, where dissipation of the vacuum potential during inflation is the mechanism for structure formation. The bispectrum is non--zero because of the self--interaction of the scalar field. We compare the predictions with those of standard, or `supercooled', inflationary models, and consider the detectability of these levels of non--Gaussianity in the bispectrum of the cosmic microwave background. We...
Source: http://arxiv.org/abs/astro-ph/0205152v2
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Sep 19, 2013
09/13
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R. Tojeiro; P. G. Castro; A. F. Heavens; S. Gupta
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eye 38
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We present a search for non-Gaussianity in the WMAP first-year data using the two-point correlation function of maxima and minima in the temperature map. We find evidence for non-Gaussianity on large scales, whose origin appears to be associated with unsubstracted foregrounds, but which is not entirely clear. The signal appears to be associated most strongly with cold spots, and is more pronounced in the Southern galactic hemisphere. Removal of the region of sky near the galactic plane, or...
Source: http://arxiv.org/abs/astro-ph/0507096v2
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45
Sep 22, 2013
09/13
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R. G. Mann; S. Oliver; R. Carballo; A. Franceschini; M. Rowan-Robinson; A. F. Heavens; M. Kontizas; D. Elbaz; A. Dapergolas; E. Kontizas; G. L. Granato; L. Silva; D. Rigopoulou; J. I. Gonzalez-Serrano; A. Verma; S. Serjeant; A. Efstathiou; P. P. van der Werf
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eye 45
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We present results from a deep mid-IR survey of the Hubble Deep Field South (HDF-S) region performed at 7 and 15um with the CAM instrument on board ISO. We found reliable optical/near-IR associations for 32 of the 35 sources detected in this field by Oliver et al. (2002, Paper I): eight of them were identified as stars, one is definitely an AGN, a second seems likely to be an AGN, too, while the remaining 22 appear to be normal spiral or starburst galaxies. Using model spectral energy...
Source: http://arxiv.org/abs/astro-ph/0201510v2
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Sep 19, 2013
09/13
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A. F. Heavens; T. D. Kitching; L. Verde
texts
eye 65
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The Fisher matrix approach (Fisher 1935) allows one to calculate in advance how well a given experiment will be able to estimate model parameters, and has been an invaluable tool in experimental design. In the same spirit, we present here a method to predict how well a given experiment can distinguish between different models, regardless of their parameters. From a Bayesian viewpoint, this involves computation of the Bayesian evidence. In this paper, we generalise the Fisher matrix approach...
Source: http://arxiv.org/abs/astro-ph/0703191v2
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Sep 18, 2013
09/13
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A. N. Taylor; T. D. Kitching; D. J. Bacon; A. F. Heavens
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eye 59
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We adapt the Jain--Taylor (2003) shear-ratio geometric lensing method to measure the dark energy equation of state, and its time derivative from dark matter haloes in cosmologies with arbitrary spatial curvature. The full shear-ratio covariance matrix is calculated for lensed sources, including the intervening large-scale structure and photometric redshift errors as additional sources of noise, and a maximum likelihood method for applying the test is presented. Combining with the expected...
Source: http://arxiv.org/abs/astro-ph/0606416v2
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40
Sep 18, 2013
09/13
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W. E. Ballinger; A. N. Taylor; A. F. Heavens; H. Tadros
texts
eye 40
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We have constrained the redshift-distortion parameter $\beta \equiv \Omega^{0.6}/b$ and the real-space power spectrum of the IRAS PSCz survey using a spherical-harmonic redshift-distortion analysis combined with a data compression method which is designed to deal with correlated parameters. Our latest result, $\beta=0.4 \pm 0.1$, strongly rules out $\beta=1$.
Source: http://arxiv.org/abs/astro-ph/0005094v1
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133
Sep 17, 2013
09/13
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H. Gil-Marín; C. Wagner; L. Verde; R. Jimenez; A. F. Heavens
texts
eye 133
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Comparing clustering of differently biased tracers of the dark matter distribution offers the opportunity to reduce the cosmic variance error in the measurement of certain cosmological parameters. We develop a formalism that includes bias non-linearities and stochasticity. Our formalism is general enough that can be used to optimise survey design and tracers selection and optimally split (or combine) tracers to minimise the error on the cosmologically interesting quantities. Our approach...
Source: http://arxiv.org/abs/1003.3238v3
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60
Sep 21, 2013
09/13
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A. Kiessling; A. F. Heavens; A. N. Taylor
texts
eye 60
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A new cosmic shear analysis pipeline SUNGLASS (Simulated UNiverses for Gravitational Lensing Analysis and Shear Surveys) is introduced. SUNGLASS is a pipeline that rapidly generates simulated universes for weak lensing and cosmic shear analysis. The pipeline forms suites of cosmological N-body simulations and performs tomographic cosmic shear analysis using line-of-sight integration through these simulations while saving the particle lightcone information. Galaxy shear and convergence...
Source: http://arxiv.org/abs/1011.1476v1
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47
Sep 22, 2013
09/13
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A. Kiessling; A. N. Taylor; A. F. Heavens
texts
eye 47
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Fisher Information Matrix methods are commonly used in cosmology to estimate the accuracy that cosmological parameters can be measured with a given experiment, and to optimise the design of experiments. However, the standard approach usually assumes both data and parameter estimates are Gaussian-distributed. Further, for survey forecasts and optimisation it is usually assumed the power-spectra covariance matrix is diagonal in Fourier-space. But in the low-redshift Universe, non-linear...
Source: http://arxiv.org/abs/1103.3245v1
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Sep 18, 2013
09/13
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H. Tadros; W. E. Ballinger; A. N. Taylor; A. F. Heavens; G. Efstathiou; W. Saunders; C. S. Frenk; O. Keeble; R. McMahon; S. J. Maddox; S. Oliver; M. Rowan-Robinson; W. J. Sutherland S. D. M. White
texts
eye 58
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We apply the formalism of spherical harmonic decomposition to the galaxy density field of the IRAS PSCz redshift survey. The PSCz redshift survey has almost all-sky coverage and includes IRAS galaxies to a flux limit of 0.6 Jy. Using maximum likelihood methods to examine (to first order) the distortion of the galaxy pattern due to redshift coordinates, we have measured the parameter \beta= \Omega^{0.6}/b. We also simultaneously measure (a) the undistorted amplitude of perturbations in the...
Source: http://arxiv.org/abs/astro-ph/9901351v1
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Sep 23, 2013
09/13
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T. D. Kitching; A. N. Taylor; A. F. Heavens
texts
eye 35
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We present an investigation into the potential effect of systematics inherent in multi-band wide field surveys on the dark energy equation of state determination for two 3D weak lensing methods. The weak lensing methods are a geometric shear-ratio method and 3D cosmic shear. The analysis here uses an extension of the Fisher matrix framework to jointly include photometric redshift systematics, shear distortion systematics and intrinsic alignments. We present results for DUNE and Pan-STARRS...
Source: http://arxiv.org/abs/0801.3270v1
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Sep 19, 2013
09/13
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M. R. S. Hawkins; D. Clements; J. W. Fried; A. F. Heavens; P. Véron; E. M. Minty; P. van der Werf
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eye 32
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We report the discovery of a new gravitational lens candidate Q2138-431AB, comprising two quasar images at a redshift of 1.641 separated by 4.5 arcsecs. The spectra of the two images are very similar, and the redshifts agree to better than 115 km.sec$^{-1}$. The two images have magnitudes $B_J = 19.8$ and $B_J = 21.0$, and in spite of a deep search and image subtraction procedure, no lensing galaxy has been found with $R < 23.8$. Modelling of the system configuration implies that the...
Source: http://arxiv.org/abs/astro-ph/9709049v1
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7.0
Jun 29, 2018
06/18
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K. C. Chambers; E. A. Magnier; N. Metcalfe; H. A. Flewelling; M. E. Huber; C. Z. Waters; L. Denneau; P. W. Draper; D. Farrow; D. P. Finkbeiner; C. Holmberg; R. White; W. M. Wood-Vasey; R. Wyse; J. Koppenhoefer; P. A. Price; R. P. Saglia; E. F. Schlafly; S. J. Smartt; W. Sweeney; R. J. Wainscoat; W. S. Burgett; T. Grav; J. N. Heasley; K. W. Hodapp; R. Jedicke; N. Kaiser; R. -P. Kudritzki; G. A. Luppino; R. H. Lupton; D. G. Monet; J. S. Morgan; P. M. Onaka; C. W. Stubbs; J. L. Tonry; E. Banados;...
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Pan-STARRS1 has carried out a set of distinct synoptic imaging sky surveys including the $3\pi$ Steradian Survey and the Medium Deep Survey in 5 bands (\grizy). The mean 5$\sigma$ point source limiting sensitivities in the stacked 3$\pi$ Steradian Survey in \grizy are (23.3, 23.2, 23.1, 22.3, 21.4) respectively. The upper bound on the systematic uncertainty in the photometric calibration across the sky is 7-12 millimag depending on the bandpass. The systematic uncertainty of the astrometric...
Topics: Earth and Planetary Astrophysics, Astrophysics, Solar and Stellar Astrophysics, Instrumentation and...
Source: http://arxiv.org/abs/1612.05560
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Sep 18, 2013
09/13
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Louisa A. Nolan; J. S. Dunlop; B. Panter; Raul Jimenez; A. F. Heavens; G. Smith
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eye 63
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We present the first results from a study designed to test whether, given high-quality spectrophotometry spanning the mid-UV--optical wavelength regime, it is possible to distinguish the metal content (Z) and star-formation history (sfh) of individual elliptical galaxies with sufficient accuracy to establish whether their formation history is linked to their detailed morphology and position on the Fundamental Plane. From a detailed analysis of UV-optical spectrophotometry of the `cuspy'...
Source: http://arxiv.org/abs/astro-ph/0605417v3
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2.0
Jun 29, 2018
06/18
by
T. D. Kitching; A. F. Heavens
texts
eye 2
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Measurements of the power spectrum from large-scale structure surveys have to date assumed an equal-time approximation, where the full cross-correlation power spectrum of the matter density field evaluated at different times (or distances) has been approximated either by the power spectrum at a fixed time, or in an improved fashion, by a geometric mean $P(k; r_1, r_2)=[P(k; r_1) P(k; r_2)]^{1/2}$. In this paper we investigate the expected impact of the geometric mean ansatz, and present an...
Topics: Astrophysics, Cosmology and Nongalactic Astrophysics
Source: http://arxiv.org/abs/1612.00770
