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We have developed a method based on wavelets to obtain the true underlying smooth density from a point distribution. The goal has been to reconstruct the density field in an optimal way ensuring that the morphology of the reconstructed…

Astrophysics · Physics 2009-11-13 V. J. Martinez , J. -L. Starck , E. Saar , D. L. Donoho , S. Reynolds , P. de la Cruz , S. Paredes

A statistical study of global galaxy parameters can help to improve our understanding of galaxy formation processes. In this paper we present the analysis of global galaxy parameters based on optical and near-infrared observations of a…

Astrophysics · Physics 2009-10-30 R. de Grijs

First-order statistics of scattered light is described using the representation of probability density cloud which visualizes a two-dimensional distribution for complex amplitude. The geometric parameters of the cloud are studied in detail…

Instrumentation and Methods for Astrophysics · Physics 2017-08-02 Natalia Yaitskova

While galactic bulges may contain no significant dust of their own, the dust within galaxy discs can strongly attenuate the light from their embedded bulges. Furthermore, such dust inhibits the ability of observationally-determined…

Astrophysics · Physics 2012-04-26 Alister W. Graham , C. C. Worley

We propose a new method to estimate the photometric redshift of galaxies by using the full galaxy image in each measured band. This method draws from the latest techniques and advances in machine learning, in particular Deep Neural…

Instrumentation and Methods for Astrophysics · Physics 2016-06-16 Ben Hoyle

In most direct estimates of the mass density (visible or dark) of the Universe, a central input parameter is the luminosity density of the Universe. Here we consider the measurement of this luminosity density from red-shift surveys, as a…

Astrophysics · Physics 2009-11-06 Michael Joyce , Francesco Sylos Labini

The multiplicity function (MF) of groups and clusters of galaxies is determined using galaxy catalogues extracted from a set of Digitized Palomar Sky Survey (DPOSS) plates. The two different types of structures (of low and high richness)…

Astrophysics · Physics 2009-11-07 E. Puddu , E. De Filippis , G. Longo , S. Andreon , R. R. Gal

The mathematical theory of gravitational lensing has revealed many generic and global properties. Beginning with multiple imaging, we review Morse-theoretic image counting formulas and lower bound results, and complex-algebraic upper bounds…

Astrophysics of Galaxies · Physics 2014-11-20 A. O. Petters , M. C. Werner

We present results from a comprehensive lensing analysis in HST data, of the complete CLASH cluster sample. We identify new multiple-images previously undiscovered allowing improved or first constraints on the cluster inner mass…

Given points $p_1, \dots, p_n$ in $\mathbb{R}^d$, how do we find a point $x$ which maximizes $\frac{1}{n} \sum_{i=1}^n e^{-\|p_i - x\|^2}$? In other words, how do we find the maximizing point, or mode of a Gaussian kernel density estimation…

Data Structures and Algorithms · Computer Science 2019-12-18 Jasper C. H. Lee , Jerry Li , Christopher Musco , Jeff M. Phillips , Wai Ming Tai

Future large scale structure surveys will provide increasingly tight constraints on our cosmological model. These surveys will report results on the distance scale and growth rate of perturbations through measurements of Baryon Acoustic…

Cosmology and Nongalactic Astrophysics · Physics 2016-12-07 Martin White

Number counts of galaxy clusters offer a very promising probe of the Dark Energy (DE) equation-of-state parameter, $w$. The basic goal is to measure abundances of these objects as a function of redshift, compare this to a theoretical…

Astrophysics · Physics 2009-09-29 M. Davis , B. F. Gerke , A. L. Coil , M. C. Cooper , R. Yan , J. A. Newman , S. M. Faber , D. Koo , P. Guhathakurta

We present a survey of mass profiles and mass-to-light ratios of eight typical galaxy clusters at a common redshift (z ~ 0.2). We use weak gravitational lensing as a probe because it is unique in avoiding any assumptions about the dynamical…

If the accelerated expansion of the universe is due to a modification of general relativity at late times, it is likely that the growth of structure on large scales would also display deviations from the standard cosmology. We investigate…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-27 Marcell Howard , Arthur Kosowsky , Georgios Valogiannis

In the present paper we introduce new optimization algorithms for the task of density ratio estimation. More precisely, we consider extending the well-known KMM method using the construction of a suitable loss function, in order to…

Machine Learning · Computer Science 2023-09-15 Cristian Daniel Alecsa

Understanding the formation and evolution of galaxy populations requires robust classification and characterisation techniques that jointly account for internal galaxy properties and environment. We analyse $5,306$ galaxies from the Galaxy…

Astrophysics of Galaxies · Physics 2026-05-25 Fan Dai , Ranjan Maitra , Ivan K. Baldry

Directional data consist of observations distributed on a (hyper)sphere, and appear in many applied fields, such as astronomy, ecology, and environmental science. This paper studies both statistical and computational problems of kernel…

Machine Learning · Statistics 2021-10-18 Yikun Zhang , Yen-Chi Chen

Analysing the weak lensing distortions of the images of faint background galaxies provides a means to constrain the average mass distribution of cluster galaxies and potentially to test the extent of their dark matter haloes as a function…

Astrophysics · Physics 2009-10-30 Bernhard Geiger , Peter Schneider

Generalized geometry provides the framework for a systematic approach to non-symmetric metric gravity theory and naturally leads to an Einstein-Kalb-Ramond gravity theory with totally anti-symmetric contortion. The approach is related to…

High Energy Physics - Theory · Physics 2016-11-03 Branislav Jurco , Fech Scen Khoo , Peter Schupp , Jan Vysoky

The detection of galaxy clusters in present and future surveys enables measuring mass-to-light ratios, clustering properties or galaxy cluster abundances and therefore, constraining cosmological parameters. We present a new technique for…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-17 Begoña Ascaso , David Wittman , Narciso Benítez , the DLS collaboration
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