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We present photometric redshifts and associated probability distributions for all detected sources in the Extended Chandra Deep Field South (ECDFS). The work makes use of the most up-to-date data from the Cosmic Assembly Near-IR Deep Legacy…

We present the Fast Chebyshev Transform (FCT), a fast, randomized algorithm to compute a Chebyshev approximation of functions in high-dimensions from the knowledge of the location of its nonzero Chebyshev coefficients. Rather than sampling…

Numerical Analysis · Mathematics 2023-10-03 Dalton Jones , Pierre-David Letourneau , Matthew J. Morse , M. Harper Langston

In recent years, a variety of meshless methods have been developed to solve partial differential equations in complex domains. Meshless methods discretize the partial differential equations over scattered points instead of grids. Radial…

Numerical Analysis · Mathematics 2021-06-17 Naman Bartwal , Shantanu Shahane , Somnath Roy , Surya Pratap Vanka

Analytic distribution functions (DFs) for the Galactic disc are discussed. The DFs depend on action variables and their predictions for observable quantities are explored under the assumption that the motion perpendicular to the Galactic…

Astrophysics of Galaxies · Physics 2015-05-14 James Binney

The determination of the galaxy luminosity function is an active and fundamental field in observational cosmology. In this paper we propose a cost effective way of measuring galaxy luminosity functions at faint magnitudes. Our technique…

Astrophysics · Physics 2009-10-28 M. U. SubbaRao , A. J. Connolly , A. S. Szalay , D. C. Koo

The location of objects on the celestial sphere is a fundamental measurement in astronomy, and the distribution of these objects within the Milky Way is important for understanding their evolution as well as the large scale structure of the…

Astrophysics of Galaxies · Physics 2015-05-20 M. M. McKinnon

We introduce a polynomial time algorithm for optimizing the class of star-convex functions, under no restrictions except boundedness on a region about the origin, and Lebesgue measurability. The algorithm's performance is polynomial in the…

Data Structures and Algorithms · Computer Science 2016-05-13 Jasper C. H. Lee , Paul Valiant

We present a new approach for image reconstruction and weak lensing measurements with interferometers. Based on the shapelet formalism presented in Refregier (2001), object images are decomposed into orthonormal Hermite basis functions. The…

Astrophysics · Physics 2009-11-06 Tzu-Ching Chang , Alexandre Refregier

Given a galaxy image, one cannot simply measure its flexion. An image's spin one and three shape properties, typically associated with F- and G-flexion, are actually complicated functions of the galaxy's intrinsic shape and the telescope's…

Cosmology and Nongalactic Astrophysics · Physics 2014-05-26 Rebecca Sobel Levinson

We propose a new technique to directly measure the shapes of dark matter halos of galaxies using weak gravitational lensing. Extending the standard galaxy-galaxy lensing method, we show that the shape parameters of the mass distribution of…

Astrophysics · Physics 2009-10-31 Priyamvada Natarajan , Alexandre Refregier

We use automated surface photometry and pattern classification techniques to morphologically classify galaxies. The two-dimensional light distribution of a galaxy is reconstructed using Fourier series fits to azimuthal profiles computed in…

Astrophysics · Physics 2009-11-07 S. C. Odewahn , S. H. Cohen , R. A. Windhorst , N. S. Philip

Determining the distribution of redshifts for galaxies in wide-field photometric surveys is essential for robust cosmological studies of weak gravitational lensing. We present the methodology, calibrated redshift distributions, and…

In today's modern wide-field galaxy surveys, there is the necessity for parametric surface brightness decomposition codes characterised by accuracy, small degree of user intervention, and high degree of parallelisation. We try to address…

Astrophysics of Galaxies · Physics 2023-03-03 Luca Tortorelli , Amata Mercurio

Chebyshev interpolation polynomials exhibit the exponential approximation property to analytic functions on a cube. Based on the Chebyshev interpolation polynomial approximation, we propose iterative polynomial approximation algorithms to…

Signal Processing · Electrical Eng. & Systems 2025-04-22 Cheng Cheng , Qiyu Sun , Cong Zheng

Hypercomplex image processing extends conventional techniques in a unified paradigm encompassing algebraic and geometric principles. This work leverages quaternions and the two-dimensional orthogonal planes split framework (splitting of a…

A long-held astronomical vision is to realize diffraction-limited optical aperture synthesis over kilometer baselines. This will enable imaging of stellar surfaces and their environments, show their evolution over time, and reveal…

Instrumentation and Methods for Astrophysics · Physics 2015-06-22 Dainis Dravins , Tiphaine Lagadec

The current generation of Imaging Atmospheric Cherenkov telescopes are allowing the sky to be probed with greater sensitivity than ever before in the energy range around and above 100 GeV. To minimise the systematic errors on derived fluxes…

Instrumentation and Methods for Astrophysics · Physics 2015-05-19 Sam Nolan , Gerd Puehlhofer , Cameron Rulten

We extend models of our Galaxy based on distribution functions (DFs) that are analytic functions of the action integrals to extended distribution functions (EDFs), which have an analytic dependence on metallicity as well. We use a simple,…

Astrophysics of Galaxies · Physics 2015-06-03 Jason L. Sanders , James Binney

Piecewise Polynomials (PPs) are utilized in several engineering disciplines, like trajectory planning, to approximate position profiles given in the form of a set of points. While the approximation target along with domain-specific…

Machine Learning · Computer Science 2024-05-09 Hannes Waclawek , Stefan Huber

We examine a general framework for visualizing datasets of high (> 2) dimensionality, and demonstrate it using the morphology of galaxies at moderate redshifts. The distributions of various populations of such galaxies are examined in a…

Astrophysics · Physics 2007-05-23 A. Naim , K. U. Ratnatunga , R. E. Griffiths