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The so-called Limber equation is widely used in the literature to relate the projected angular clustering of galaxies to the spatial clustering of galaxies in an approximate way. This paper gives estimates of where the regime of…

Astrophysics · Physics 2009-11-11 P. Simon

We develop a set of machine-learning based cosmological emulators, to obtain fast model predictions for the $C(\ell)$ angular power spectrum coefficients characterising tomographic observations of galaxy clustering and weak gravitational…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-30 Marco Bonici , Luca Biggio , Carmelita Carbone , Luigi Guzzo

Angular power spectra are an important measure of the angular clustering of a given distribution. In Cosmology, they are applied to such vastly different observations as galaxy surveys that cover a fraction of the sky and the Cosmic…

Astrophysics · Physics 2007-11-15 Brett Hayes , Robert Brunner , Volodymyr Kindratenko

The significant increase in precision that will be achieved by Stage IV cosmic shear surveys means that several currently used theoretical approximations may cease to be valid. An additional layer of complexity arises from the fact that…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-28 Anurag C. Deshpande , Thomas D. Kitching

Strong gravitational lensing by irregular mass distributions, such as galaxy clusters, is generally not well quantified by cross sections of analytic mass models. Computationally expensive ray-tracing methods have so far been necessary for…

Astrophysics · Physics 2016-08-30 C. Fedeli , M. Meneghetti , M. Bartelmann , K. Dolag , L. Moscardini

Cosmological parameter estimation from forthcoming experiments promise to reach much greater precision than current constraints. As statistical errors shrink, the required control over systematic errors increases. Therefore, models or…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-07 José Luis Bernal , Nicola Bellomo , Alvise Raccanelli , Licia Verde

In the era of precision cosmology, establishing the correct magnitude of statistical errors in cosmological parameters is of crucial importance. However, widely used approximations in galaxy surveys analyses can lead to parameter…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-07 Nicola Bellomo , José Luis Bernal , Giulio Scelfo , Alvise Raccanelli , Licia Verde

We discuss the second order contributions to lensing statistics resulting from the clustering of background sources from which galaxy shape measurements are made in weak lensing experiments. In addition to a previously discussed…

Astrophysics · Physics 2007-05-23 Asantha Cooray

Efficient computation of the angular bispectrum is an essential part of modelling large-scale structure observations, but it still remains an extremely challenging task. In this work, we compute the tree-level, unequal-time angular…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-29 Zucheng Gao , Zvonimir Vlah , Anthony Challinor

The clustering of galaxy clusters is a powerful cosmological tool, which can help to break degeneracies between parameters when combined with other cosmological observables. We aim to demonstrate its potential in constraining cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-16 Alessandra Fumagalli , Matteo Costanzi , Alexandro Saro , Tiago Castro , Stefano Borgani

We introduce two kurt-spectra to probe fourth-order statistics of weak lensing convergence maps. Using state-of-the-art numerical simulations, we study the shapes of these kurt-spectra as a function of source redshifts and smoothing angular…

Cosmology and Nongalactic Astrophysics · Physics 2022-11-16 Dipak Munshi , Hayden Lee , Cora Dvorkin , Jason D. McEwen

We review the effect of the commonly-used Limber and flat-sky approximations on the calculation of shear power spectra and correlation functions for galaxy weak lensing. These approximations are accurate at small scales, but it has been…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-17 Pablo Lemos , Anthony Challinor , George Efstathiou

The two point angular correlation function is an excellent measure of structure in the universe. To extract from it the three dimensional power spectrum, one must invert Limber's Equation. Here we perform this inversion using a Bayesian…

Astrophysics · Physics 2008-11-26 Scott Dodelson , Enrique Gaztanaga

The existence of galaxy intrinsic clustering severely hampers the weak lensing reconstruction from cosmic magnification. In paper I \citep{Yang2011}, we proposed a minimal variance estimator to overcome this problem. By utilizing the…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-21 Xinjuan Yang , Pengjie Zhang , Jun Zhang , Yu Yu

We present LimberJack.jl, a fully auto-differentiable code for cosmological analyses of 2 point auto- and cross-correlation measurements from galaxy clustering, CMB lensing and weak lensing data written in Julia. Using Julia's…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-18 J. Ruiz-Zapatero , D. Alonso , C. García-García , A. Nicola , A. Mootoovaloo , J. M. Sullivan , M. Bonici , P. G. Ferreira

We present the three-dimensional power spectrum of galaxy clustering using measurements of the angular correlation function from the second incremental release of the Two-Micron All Sky Survey (2MASS). The angular positions of galaxies out…

Astrophysics · Physics 2019-08-17 B. Allgood , G. Blumenthal , J. R. Primack

Observed galaxy clustering exhibits local transverse statistical isotropy around the line-of-sight (LOS). The variation of the LOS across a galaxy survey complicates the measurement of the observed clustering as a function of the angle to…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-17 Davide Bianchi , Héctor Gil-Marín , Rossana Ruggeri , Will J. Percival

While the direct detection of the dark-matter particle remains very challenging, the nature of dark matter could be possibly constrained by comparing the observed abundance and properties of small-scale sub-galactic mass structures with…

Astrophysics of Galaxies · Physics 2023-05-17 D. Bayer , L. V. E. Koopmans , J. P. McKean , S. Vegetti , T. Treu , C. D. Fassnacht , K. Glazebrook

Accurate covariance matrices for two-point functions are critical for inferring cosmological parameters in likelihood analyses of large-scale structure surveys. Among various approaches to obtaining the covariance, analytic computation is…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-23 Xiao Fang , Tim Eifler , Elisabeth Krause