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We develop a hybrid GNN-CNN architecture for the reconstruction of 3-dimensional continuous cosmological matter fields from discrete point clouds, provided by observed galaxy catalogs. Using the CAMELS hydrodynamical cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-06 Yurii Kvasiuk , Jordan Krywonos , Matthew C. Johnson , Moritz Münchmeyer

In this work, we study the perception problem for sampled surfaces (possibly with boundary) using tools from computational topology, specifically, how to identify their underlying topology starting from point-cloud samples in space, such as…

Computational Geometry · Computer Science 2024-10-17 Franco Coltraro , Jaume Amorós , Maria Alberich-Carramiñana , Carme Torras

Astronomical images are of crucial importance for astronomers since they contain a lot of information about celestial bodies that can not be directly accessible. Most of the information available for the analysis of these objects starts…

Numerical Analysis · Mathematics 2019-04-10 Silvia Tozza , Maurizio Falcone

Speckle Imaging based on triple correlation is a very efficient image reconstruction technique which is used to retrieve Fourier phase information of the object in presence of atmospheric turbulence. We have developed both Direct Bispectrum…

Instrumentation and Methods for Astrophysics · Physics 2014-09-17 Arun Surya , Swapan K. Saha

The gravitational coupling between large-scale perturbations and small-scale perturbations leads to anisotropic distortions of the small-scale matter distribution. The measured local small-scale power spectrum can thus be used to infer the…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-20 Hong-Ming Zhu , Tian-Xiang Mao , Ue-Li Pen

In recent years, there has been a proliferation of wide-field sky surveys to search for a variety of transient objects. Using relatively short focal lengths, the optics of these systems produce undersampled stellar images often marred by a…

Astrophysics · Physics 2009-11-13 Fang Yuan , Carl W. Akerlof

Star formation is a multi-scale problem, and only global simulations that account for the connection from the molecular cloud scale gas flow to the accreting protostar can reflect the observed complexity of protostellar systems.…

Astrophysics of Galaxies · Physics 2023-07-28 Rami Al-Belmpeisi , Vito Tuhtan , Mikkel Bregning Christensen , Rajika L Kuruwita , Troels Haugbølle

Accurately reconstructing a global spatial field from sparse data has been a longstanding problem in several domains, such as Earth Sciences and Fluid Dynamics. Historically, scientists have approached this problem by employing complex…

Computer Vision and Pattern Recognition · Computer Science 2024-08-23 Robert Sunderhaft , Logan Frank , Jim Davis

The prospect of nonparametric reconstructions of cosmological parameters from observational data sets has been a popular topic in the literature for a number of years. This has mainly taken the form of a technique based on Gaussian…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-24 Konstantinos Dialektopoulos , Jackson Levi Said , Jurgen Mifsud , Joseph Sultana , Kristian Zarb Adami

Planetary exploration increasingly relies on autonomous robotic systems capable of perceiving, interpreting, and reconstructing their surroundings in the absence of global positioning or real-time communication with Earth. Rovers operating…

In this paper, we present a novel approach to the estimation of strongly varying backgrounds in astronomical images by means of small objects removal and subsequent missing pixels interpolation. The method is based on the analysis of a…

Instrumentation and Methods for Astrophysics · Physics 2016-08-10 Adam Popowicz , Bogdan Smolka

We present a method to simulate deep sky images, including realistic galaxy morphologies and telescope characteristics. To achieve a wide diversity of simulated galaxy morphologies, we first use the shapelets formalism to parametrize the…

The gravitational coupling of a long-wavelength tidal field with small-scale density fluctuations leads to anisotropic distortions of the locally measured small-scale matter correlation function. Since the local correlation function is…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-25 Hong-Ming Zhu , Ue-Li Pen , Yu Yu , Xinzhong Er , Xuelei Chen

We propose a new reconstruction method for scalar--tensor gravity based on the use of conformal transformations. The new method allows the derivation of a set of interesting exact cosmological solutions in brans Dicke gravity as well as…

General Relativity and Quantum Cosmology · Physics 2013-11-26 Stefano Vignolo , Sante Carloni , Francesco Vietri

The observation of blank fields, regions of the sky devoid of stars down to a given threshold magnitude, constitutes one of the typical important calibration procedures required for the proper reduction of astronomical data obtained in…

Instrumentation and Methods for Astrophysics · Physics 2015-05-28 N. Cardiel , F. M. Jiménez-Esteban , J. M. Alacid , E. Solano , M. Aberasturi

A light field records numerous light rays from a real-world scene. However, capturing a dense light field by existing devices is a time-consuming process. Besides, reconstructing a large amount of light rays equivalent to multiple light…

Computer Vision and Pattern Recognition · Computer Science 2018-08-14 Mantang Guo , Hao Zhu , Guoqing Zhou , Qing Wang

An array of large observational programs using ground-based and space-borne telescopes is planned in the next decade. The forthcoming wide-field sky surveys are expected to deliver a sheer volume of data exceeding an exabyte. Processing the…

Instrumentation and Methods for Astrophysics · Physics 2023-05-26 Kana Moriwaki , Takahiro Nishimichi , Naoki Yoshida

Connecting cosmological simulations to real-world observational programs is often complicated by a mismatch in geometry: while surveys often cover highly irregular cosmological volumes, simulations are customarily performed in a periodic…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-18 Jordan Carlson , Martin White

In tomographic reconstruction, the goal is to reconstruct an unknown object from a collection of line integrals. Given a complete sampling of such line integrals for various angles and directions, explicit inverse formulas exist to…

Numerical Analysis · Mathematics 2018-01-18 Tristan van Leeuwen , Simon Maretzke , K. Joost Batenburg

We are developing automated systems to provide homogeneous calibration meta-data for heterogeneous imaging data, using the pixel content of the image alone where necessary. Standardized and complete calibration meta-data permit generative…

Astrophysics · Physics 2009-11-13 David W. Hogg , Dustin Lang