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A piecewise Chebyshevian spline space is good for design when it possesses a B-spline basis and this property is preserved under knot insertion. The interest in such kind of spaces is justified by the fact that, similarly as for polynomial…

Numerical Analysis · Mathematics 2021-11-12 Carolina Vittoria Beccari , Giulio Casciola , Lucia Romani

The imaging performance of tomographic deconvolution phase microscopy can be described in terms of the phase optical transfer function (POTF) which, in turn, depends on the illumination profile. To facilitate the optimization of the…

Optics · Physics 2021-05-12 Jianhui Huang , Yijun Bao , Thomas K. Gaylord

From Rybicki's analysis using the Fourier slice theorem, mathematically it is possible to reproduce uniquely an edge-on axisymmetric galaxy's 3D light distribution from its 2D surface brightness. Utilizing galaxies from a cosmological…

Astrophysics of Galaxies · Physics 2021-08-18 Richard J. Long , Shengdong Lu , Dandan Xu

Kinematic weak lensing describes the distortion of a galaxy's projected velocity field due to lensing shear, an effect recently reported for the first time by Gurri et al. based on a sample of 18 galaxies at $z \sim 0.1$. In this paper, we…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-08 Brian DiGiorgio , Kevin Bundy , Kyle B. Westfall , Alexie Leauthaud , David Stark

In this paper, we propose compactly supported radial basis functions for solving some well- known classes of astrophysics problems categorized as non-linear singular initial ordinary dif- ferential equations on a semi-infinite domain. To…

Numerical Analysis · Mathematics 2016-05-31 Kourosh Parand , Mohammad Hemami

In this paper, we introduce the class of $(\beta,\gamma)$-Chebyshev functions and corresponding points, which can be seen as a family of {\it generalized} Chebyshev polynomials and points. For the $(\beta,\gamma)$-Chebyshev functions, we…

Numerical Analysis · Mathematics 2021-11-23 Stefano De Marchi , Giacomo Elefante , Francesco Marchetti

Weak gravitational lensing requires precise measurements of galaxy shapes and therefore an accurate knowledge of the PSF model. The latter can be a source of systematics that affect the shear two-point correlation function. A key stake of…

Recent years have witnessed the introduction and development of extremely fast rational function algorithms. Many ideas in this realm arose from polynomial-based linear-algebraic algorithms. However, polynomial approximation is occasionally…

Numerical Analysis · Mathematics 2025-10-03 James Chok , Geoffrey M. Vasil

Modern cosmological surveys such as the Hyper Suprime-Cam (HSC) survey produce a huge volume of low-resolution images of both distant galaxies and dim stars in our own galaxy. Being able to automatically classify these images is a…

Instrumentation and Methods for Astrophysics · Physics 2020-10-14 Imène R. Goumiri , Amanda L. Muyskens , Michael D. Schneider , Benjamin W. Priest , Robert E. Armstrong

With the advent of several galaxy surveys targeting star-forming galaxies, it is important to have models capable of interpreting their spatial distribution in terms of astrophysical and cosmological parameters. To address this need, we…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-04 Sara Ortega-Martinez , Sergio Contreras , Raul Angulo

Weak gravitational lensing has the potential to place tight constraints on the equation of the state of dark energy. However, this will only be possible if shear measurement methods can reach the required level of accuracy. We present a new…

Instrumentation and Methods for Astrophysics · Physics 2015-05-13 Guldariya Nurbaeva , Malte Tewes , Frederic Courbin , Georges Meylan

The EFAR project is a study of 736 candidate early-type galaxies in 84 clusters lying in two regions towards Hercules-Corona Borealis and Perseus-Cetus at distances $cz \approx 6000-15000$ km/s. In this paper we describe a new method of…

An extension of Schwarzschild's galaxy-building technique is presented that, for the first time, enables one to build Schwarzschild models with known distribution functions (DFs). The new extension makes it possible to combine a DF that…

Astrophysics · Physics 2009-10-31 Ralf M. Hafner , N. Wyn Evans , Walter Dehnen , James Binney

We present new tests to identify stationary position-dependent additive shear biases in weak gravitational lensing data sets. These tests are important diagnostics for currently ongoing and planned cosmic shear surveys, as such biases…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-24 Edo van Uitert , Peter Schneider

This is the first paper of a series aiming at investigating galaxy formation and evolution in the giant-void class of the Lemaitre-Tolman-Bondi (LTB) models that best fits current cosmological observations. Here we investigate the…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-18 A. Iribarrem , P. Andreani , C. Gruppioni , S. February , M. B. Ribeiro , S. Berta , E. Le Floc'h , B. Magnelli , R. Nordon , P. Popesso , F. Pozzi , L. Riguccini

Purpose: Cherenkov radiation carries the potential of direct in-water dose measurements, but its precision is currently limited by a strong anisotropy. Taking advantage of polarization imaging, this work proposes a new approach for high…

Medical Physics · Physics 2022-10-12 Emily Cloutier , Louis Archambault , Luc Beaulieu

The search for a luminosity function for galaxies both alternative or companion to a Schechter function is a key problem in the reduction of data from catalogs of galaxies. Two luminosity functions for galaxies can be built starting from…

Astrophysics · Physics 2011-09-20 Lorenzo Zaninetti

We developed a Deep Convolutional Neural Network (CNN), used as a classifier, to estimate photometric redshifts and associated probability distribution functions (PDF) for galaxies in the Main Galaxy Sample of the Sloan Digital Sky Survey…

Instrumentation and Methods for Astrophysics · Physics 2018-12-26 Johanna Pasquet , Emmanuel Bertin , Marie Treyer , Stéphane Arnouts , Dominique Fouchez

Multiple image gravitational lens systems, and especially quads are invaluable in determining the amount and distribution of mass in galaxies. This is usually done by mass modeling using parametric or free-form methods. An alternative way…

Astrophysics of Galaxies · Physics 2015-10-28 Addishiwot G. Woldesenbet , Liliya L. R. Williams

Context. The increase in sensitivity of Imaging Atmospheric Cherenkov Telescopes (IACTs) has lead to numerous detections of extended $\gamma$-ray sources at TeV energies, sometimes of sizes comparable to the instrument's field of view…

Instrumentation and Methods for Astrophysics · Physics 2018-11-07 Ie. Vovk , M. Strzys , C. Fruck