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In this paper we deal with the problem of chromaticity, i.e. apparent position variation of stellar images with their spectral distribution, using neural networks to analyse and process astronomical images. The goal is to remove this…

Astrophysics · Physics 2009-11-13 M. Gai , R. Cancelliere

Optimal error estimation is key to achieve accurate photometry and astrometry. Stellar fluxes and positions in high angular resolution images are typically measured with PSF fitting routines, such as StarFinder. However, the formal…

Instrumentation and Methods for Astrophysics · Physics 2022-08-12 E. Gallego-Cano , R. Schödel , A. T. Gallego-Calvente , A. M. Ghez

The Spatial Sensitivity Function (SSF) is used to quantify a detector's sensitivity to a spatially-distributed input signal. By weighting the incoming signal with the SSF and integrating, the overall scalar response of the detector can be…

Instrumentation and Methods for Astrophysics · Physics 2014-02-11 N. K. Malakar , A. J. Mesiti , K. H. Knuth

This paper introduces a probability density estimator based on Green's function identities. A density model is constructed under the sole assumption that the probability density is differentiable. The method is implemented as a binary…

Machine Learning · Statistics 2012-08-22 Peter Kovesarki , Ian C. Brock , A. Elizabeth Nuncio Quiroz

A method to calculate exact Green's functions on lattices in various dimensions is presented. Expressions in terms of generalized hypergeometric functions in one or more variables are obtained for various examples by relating the resolvent…

Mathematical Physics · Physics 2014-09-30 Koushik Ray

Star trackers are primarily optical devices that are used to estimate the attitude of a spacecraft by recognising and tracking star patterns. Currently, most star trackers use conventional optical sensors. In this application paper, we…

Computer Vision and Pattern Recognition · Computer Science 2019-07-11 Tat-Jun Chin , Samya Bagchi , Anders Eriksson , Andre van Schaik

Let $L$ be a second-order, homogeneous, constant (complex) coefficient elliptic system in ${\mathbb{R}}^n$. The goal of this article is provide a qualitative and quantitative study of the nature of the Green function associated with the…

Analysis of PDEs · Mathematics 2026-03-13 Martin Dindoš , Dorina Mitrea , Irina Mitrea , Marius Mitrea

Spatial intensity moments computed on images can be used as a probe of the centroid, size, and orientation of pixelized sources such as stars and galaxies. However, all measurements made on images suffer from errors due to undersampling and…

Instrumentation and Methods for Astrophysics · Physics 2020-12-11 Andrew K. Bradshaw

Accurate estimation of photometric redshifts (photo-$z$s) is crucial for cosmological surveys. Various methods have been developed for this purpose, such as template fitting methods and machine learning techniques, each with its own…

In the next decade, many optical surveys will aim to tackle the question of dark energy nature, measuring its equation of state parameter at the permil level. This requires trusting the photometric calibration of the survey with a precision…

We introduce a quantum dot orbital tight-binding non-equilibrium Green's function approach for the simulation of novel solar cell devices where both absorption and conduction are mediated by quantum dot states. By the use of basis states…

Mesoscale and Nanoscale Physics · Physics 2012-06-14 U. Aeberhard

Exoplanetary science is among the fastest evolving fields of today's astronomical research. Ground-based planet-hunting surveys alongside dedicated space missions (Kepler, CoRoT) are delivering an ever-increasing number of exoplanets, now…

Instrumentation and Methods for Astrophysics · Physics 2011-11-28 M. Tessenyi , M. Ollivier , G. Tinetti , J. P. Beaulieu , V. Coudé du Foresto , T. Encrenaz , G. Micela , B. Swinyard , I. Ribas , A. Aylward , J. Tennyson , M. R. Swain , A. Sozzetti , G. Vasisht , P. Deroo

We are using computer models to explore the observational sensitivity to changes in atmospheric and surface properties, and the detectability of biosignatures, in the globally averaged spectra and light-curves of the Earth. Using AIRS…

Astrophysics · Physics 2016-08-30 G. Tinetti , V. S. Meadows , D. Crisp , W. Fong , N. Kiang , E. Fishbein , T. Velusamy , E. Bosc , M. Turnbull

Current parameter estimation techniques rely on photodetectors which have low brightness and thus are based on gathering averaged statistics. Recently it was claimed that perfect photodetction will change the nature of sensing algorithms…

Quantum Physics · Physics 2016-04-12 Tuvia Gefen , David A. Herrera-Martí , Alex Retzker

We explore the sensitivity of limb darkening coefficients computed from stellar atmosphere models to different least-squares fitting methods. We demonstrate that conventional methods are strongly biased to fitting the stellar limb. Our…

Astrophysics · Physics 2008-11-26 David Heyrovsky

Cluster-scale strong lensing is a powerful tool for exploring the properties of dark matter and constraining cosmological models. However, due to the complex parameter space, pixelized strong lens modeling in galaxy clusters is…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-07 Yushan Xie , Huanyuan Shan , Nan Li , Ran Li , Eric Jullo , Chen Su , Xiaoyue Cao , Jean-Paul Kneib , Ana Acebron , Mengfan He , Ji Yao , Chunxiang Wang , Jiadong Li , Yin Li

One of the most useful techniques in astronomical instrumentation is image slicing. It enables a spectrograph to have a more compact angular slit, whilst retaining throughput and increasing resolving power. Astrophotonic components like the…

Direct detection of exoplanets requires high dynamic range imaging. Coronagraphs could be the solution, but their performance in space is limited by wavefront errors (manufacturing errors on optics, temperature variations, etc.), which…

Instrumentation and Methods for Astrophysics · Physics 2015-05-14 Raphael Galicher , Pierre Baudoz , Gerard Rousset , Julien Totems , Marion Mas

Classical and more recently deep computer vision methods are optimized for visible spectrum images, commonly encoded in grayscale or RGB colorspaces acquired from smartphones or cameras. A more uncommon source of images exploited in the…

Computer Vision and Pattern Recognition · Computer Science 2020-01-29 Caio C. V. da Silva , Keiller Nogueira , Hugo N. Oliveira , Jefersson A. dos Santos

The prospect of combining integral field spectroscopy with the solar gravitational lens (SGL) to spectrally and spatially resolve the surfaces and atmospheres of extrasolar planets is investigated. The properties of hyperbolic orbits…

Instrumentation and Methods for Astrophysics · Physics 2022-05-02 Alexander Madurowicz , Bruce Macintosh
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