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Non-parametric estimation of a multivariate density estimation is tackled via a method which combines traditional local smoothing with a form of global smoothing but without imposing a rigid structure. Simulation work delivers encouraging…

Methodology · Statistics 2016-10-10 Adelchi Azzalini

In this third paper of a series on radio weak lensing for cosmology with the Square Kilometre Array, we scrutinise synergies between cosmic shear measurements in the radio and optical/near-IR bands for mitigating systematic effects. We…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-19 Stefano Camera , Ian Harrison , Anna Bonaldi , Michael L. Brown

We suggest a set of morphological measures that we believe can help in quantifying the shapes of two-dimensional cosmological images such as galaxies, clusters, and superclusters of galaxies. The method employs non-parametric morphological…

Astrophysics · Physics 2009-07-30 Nurur Rahman , Sergei F. Shandarin

Metacalibration is a recently introduced method to accurately measure weak gravitational lensing shear using only the available imaging data, without need for prior information about galaxy properties or calibration from simulations. The…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-31 Erin S. Sheldon , Eric M. Huff

Galaxy surveys are one of the most powerful means to extract the cosmological information and for a given volume the attainable precision is determined by the galaxy shot noise sigma_n^2 relative to the power spectrum P. It is generally…

Cosmology and Nongalactic Astrophysics · Physics 2009-09-02 U. Seljak , N. Hamaus , V. Desjacques

Metacalibration is a new technique for measuring weak gravitational lensing shear that is unbiased for isolated galaxy images. In this work we test metacalibration with overlapping, or ``blended'' galaxy images. Using standard…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-28 Erin S. Sheldon , Matthew R. Becker , Niall MacCrann , Michael Jarvis

As an unsupervised dimensionality reduction method, principal component analysis (PCA) has been widely considered as an efficient and effective preprocessing step for hyperspectral image (HSI) processing and analysis tasks. It takes each…

Computer Vision and Pattern Recognition · Computer Science 2018-09-18 Junjun Jiang , Jiayi Ma , Chen Chen , Zhongyuan Wang , Zhihua Cai , Lizhe Wang

In this work, an unconsolidated granular medium, made of silica microbeads, is experimentally tested in a laboratory setting. The objective is to investigate the attenuation mechanisms of vertically polarized seismic waves traveling at the…

Geophysics · Physics 2021-11-16 R. Zaccherini , A. Palermo , A. Marzani , A. Colombi , V. K. Dertimanis , E. N. Chatzi

An efficient adaptive algorithm for the removal of Salt and Pepper noise from gray scale and color image is presented in this paper. In this proposed method first a 3X3 window is taken and the central pixel of the window is considered as…

Computer Vision and Pattern Recognition · Computer Science 2017-03-08 Sujaya Kumar Sathua , Arabinda Dash , Aishwaryarani Behera

We present a Bayesian parametric component separation method for polarised microwave sky maps. We solve jointly for the primary cosmic microwave background (CMB) signal and the main Galactic polarised foreground components. For the latter,…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-12 Roger de Belsunce , Steven Gratton , George Efstathiou

Weak gravitational lensing has the potential to constrain cosmological parameters to high precision. However, as shown by the Shear TEsting Programmes (STEP) and GRavitational lEnsing Accuracy Testing (GREAT) Challenges, measuring galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Tomasz Kacprzak , Joe Zuntz , Barnaby Rowe , Sarah Bridle , Alexandre Refregier , Adam Amara , Lisa Voigt , Michael Hirsch

In state space models, smoothing refers to the task of estimating a latent stochastic process given noisy measurements related to the process. We propose an unbiased estimator of smoothing expectations. The lack-of-bias property has…

Methodology · Statistics 2018-09-07 Pierre E. Jacob , Fredrik Lindsten , Thomas B. Schön

A frequently occurring challenge in experimental and numerical observation is how to resolve features, such as spectral peaks - with center, width, height - and derivatives from measured data with unavoidable noise. Therefore, we develop a…

Data Analysis, Statistics and Probability · Physics 2025-10-03 Bert Mulder , Ad Lagendijk , Willem L. Vos

We derive an estimator of weak gravitational lensing shear from background galaxy images that avoids noise-induced biases through a rigorous Bayesian treatment of the measurement. The derived shear estimator disposes with the assignment of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Gary M. Bernstein , Robert Armstrong

Pansharpening techniques aim at fusing low-resolution multispectral (MS) images and high-resolution panchromatic (PAN) images to produce high-resolution MS images. Despite significant progress in the field, spectral and spatial distortions…

Computer Vision and Pattern Recognition · Computer Science 2019-03-15 Joan Duran , Antoni Buades

The analysis of whole-sky galaxy surveys commonly suffers from the problems of shot-noise and incomplete sky coverage (e.g. at the Zone of Avoidance). The orthogonal set of spherical harmonics is utilized here to expand the observed galaxy…

Astrophysics · Physics 2009-10-22 O. Lahav , K. B. Fisher , Y. Hoffman , C. A. Scharf , S. Zaroubi

We propose an ambitious new method that models the intracluster medium in clusters of galaxies as a set of X-ray emitting smoothed particles of plasma. Each smoothed particle is described by a handful of parameters including temperature,…

Astrophysics · Physics 2010-11-05 J. R. Peterson , P. J. Marshall , K. Andersson

Obscuration due to Galactic emission complicates the extraction of information from cosmological surveys, and requires some combination of the (typically imperfect) modeling and subtraction of foregrounds, or the removal of part of the sky.…

Cosmology and Nongalactic Astrophysics · Physics 2011-11-14 Stephen M. Feeney , Hiranya V. Peiris , Andrew Pontzen

We present a study of weak lensing shear measurements for simulated galaxy images at radio wavelengths. We construct a simulation pipeline into which we can input galaxy images of known ellipticity, and with which we then simulate…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Prina Patel , Filipe B. Abdalla , David J. Bacon , Barnaby Rowe , Oleg Smirnov , Rob J. Beswick

Multi-band images of galaxies reveal a huge amount of information about their morphology and structure. However, inferring properties of the underlying stellar populations such as age, metallicity or kinematics from those images is…

Astrophysics of Galaxies · Physics 2021-11-03 Tobias Buck , Steffen Wolf