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We describe a new, non-parametric, method for reconstructing lensing mass distributions in multiple-image systems, and apply it to PG1115, for which time delays have recently been measured. It turns out that the image positions and the…

Astrophysics · Physics 2015-06-24 Prasenjit Saha , Liliya L. R. Williams

[Abridged] This paper aims at providing new conservative constraints to the cosmic star-formation history from the empirical modeling of mid- and far-infrared data. We perform a non-parametric inversion of galaxy counts at 15, 24, 70, 160,…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Damien Le Borgne , David Elbaz , Pierre Ocvirk , Christophe Pichon

Basement relief gravimetry is crucial in geophysics, especially for oil exploration and mineral prospecting. It involves solving an inverse problem to infer geological model parameters from observed data. The model represents basement…

Inverse problems arise in a wide spectrum of applications in fields ranging from engineering to scientific computation. Connected with the rise of interest in inverse problems is the development and analysis of regularization methods, such…

Numerical Analysis · Mathematics 2025-05-12 Abinash Nayak

Intra-pixel sensitivity variations (IPSVs) in charge-coupled devices (CCDs) and complementary metal-oxide-semiconductor (CMOS) detectors constitute a significant source of astrometric error for undersampled stellar observations. Since…

Instrumentation and Methods for Astrophysics · Physics 2026-03-12 Peipei Wang , Zihuang Cao , Chao Liu , Peng Wei , Xin Zhang , Jialu Nie

The relativistic inverse stellar structure problem determines the equation of state of the stellar matter given a knowledge of suitable macroscopic observable properties (e.g. their masses and radii) of the stars composed of that material.…

High Energy Astrophysical Phenomena · Physics 2025-02-18 Lee Lindblom , Tianji Zhou

Nonlinear parametric inverse problems appear in many applications and are typically very expensive to solve, especially if they involve many measurements. These problems pose huge computational challenges as evaluating the objective…

Numerical Analysis · Mathematics 2020-03-25 Drayton Munster , Eric de Sturler

We consider a popular nonsmooth formulation of the real phase retrieval problem. We show that under standard statistical assumptions, a simple subgradient method converges linearly when initialized within a constant relative distance of an…

Optimization and Control · Mathematics 2018-01-09 Damek Davis , Dmitriy Drusvyatskiy , Courtney Paquette

Stochastic variance reduced gradient (SVRG) is a popular variance reduction technique for accelerating stochastic gradient descent (SGD). We provide a first analysis of the method for solving a class of linear inverse problems in the lens…

Numerical Analysis · Mathematics 2022-01-19 Bangti Jin , Zehui Zhou , Jun Zou

For recovering 3D object poses from 2D images, a prevalent method is to pre-train an over-complete dictionary $\mathcal D=\{B_i\}_i^D$ of 3D basis poses. During testing, the detected 2D pose $Y$ is matched to dictionary by $Y \approx \sum_i…

Computer Vision and Pattern Recognition · Computer Science 2019-01-01 Jianqiao Wangni , Dahua Lin , Ji Liu , Kostas Daniilidis , Jianbo Shi

In this paper, we consider a modified Levenberg--Marquardt method for solving an ill-posed inverse problem where the forward mapping is not G\^ateaux differentiable. By relaxing the standard assumptions for the classical smooth setting, we…

Numerical Analysis · Mathematics 2019-09-10 Christian Clason , Vu Huu Nhu

We present the detailed study of the stellar and gaseous kinematics of the luminous early-type galaxy NGC 524 derived from the long-slit spectroscopic observations obtained with the Russian 6-m telescope and the IFU data from the SAURON…

Cosmology and Nongalactic Astrophysics · Physics 2018-03-14 I. Katkov , I. Chilingarian , O. Sil'chenko , A. Zasov , V. Afanasiev

Dynamic density-matrix renormalization provides valuable numerical information on dynamic correlations by computing convolutions of the corresponding spectral densities. Here we discuss and illustrate how and to which extent such data can…

Strongly Correlated Electrons · Physics 2007-05-23 Carsten Raas , Götz S. Uhrig

Context: Characterization of instrumental effects in astronomical imaging is important in order to extract accurate physical information from the observations. The measured image in a real optical instrument is usually represented by the…

Computer Vision and Pattern Recognition · Computer Science 2016-01-12 Adriana Gonzalez , Véronique Delouille , Laurent Jacques

The l1/l2 ratio regularization function has shown good performance for retrieving sparse signals in a number of recent works, in the context of blind deconvolution. Indeed, it benefits from a scale invariance property much desirable in the…

Optimization and Control · Mathematics 2014-11-11 Audrey Repetti , Mai Quyen Pham , Laurent Duval , Emilie Chouzenoux , Jean-Christophe Pesquet

We present a new method that simultaneously solves for cosmology and galaxy bias on non-linear scales. The method uses the halo model to analytically describe the (non-linear) matter distribution, and the conditional luminosity function…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-05 Frank van den Bosch , Surhud More , Marcello Cacciato , Houjun Mo , Xiaohu Yang

We consider the problem of reconstructing the shape of an impenetrable sound-soft obstacle from scattering measurements. The input data is assumed to be the far-field pattern generated when a plane wave impinges on an unknown obstacle from…

Numerical Analysis · Mathematics 2015-05-28 Carlos Borges , Leslie Greengard

A non-parametric smoothing method is presented that reduces noise in multi-wavelength imaging data sets. Using Principle Component Analysis (hereafter PCA) to associate pixels according to their $ugriz$-band colors, smoothing is done over…

Instrumentation and Methods for Astrophysics · Physics 2015-03-17 James Pizagno

We present a 3D Bayesian method to model the kinematics of strongly lensed galaxies from spatially-resolved emission-line observations. This technique enables us to simultaneously recover the lens-mass distribution and the source kinematics…

Astrophysics of Galaxies · Physics 2018-09-21 Francesca Rizzo , Simona Vegetti , Filippo Fraternali , Enrico Di Teodoro

We propose an unrolled algorithm approach for learning spatially adaptive parameter maps in the framework of convolutional synthesis-based $\ell_1$ regularization. More precisely, we consider a family of pre-trained convolutional filters…

Machine Learning · Computer Science 2025-10-23 Andreas Kofler , Luca Calatroni , Christoph Kolbitsch , Kostas Papafitsoros
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