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Large-scale Fourier modes of the cosmic density field are of great value for learning about cosmology because of their well-understood relationship to fluctuations in the early universe. However, cosmic variance generally limits the…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-05 Omar Darwish , Simon Foreman , Muntazir M. Abidi , Tobias Baldauf , Blake D. Sherwin , P. Daniel Meerburg

The displacement field in highly non uniformly strained crystals is obtained by addition of constraints to an iterative phase retrieval algorithm. These constraints include direct space density uniformity and also constraints to the sign…

Materials Science · Physics 2009-11-11 A. A. Minkevich , M. Gailhanou , J. -S. Micha , B. Charlet , V. Chamard , O. Thomas

Aims. Monte Carlo Radiative Transfer (MCRT) simulations are a powerful tool for understanding the role of dust in astrophysical systems and its influence on observations. However, due to the strong coupling of the radiation field and medium…

Instrumentation and Methods for Astrophysics · Physics 2023-02-01 Majda Smole , João Rino-Silvestre , Santiago González-Gaitán , Marko Stalevski

Standard cosmological perturbation theory (SPT) for the Large Scale Structure (LSS) of the Universe fails at small scales (UV) due to strong nonlinearities and to multistreaming effects. In Pietroni et al. 2011 a new framework was proposed…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Alessandro Manzotti , Marco Peloso , Massimo Pietroni , Matteo Viel , Francisco Villaescusa-Navarro

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

Upcoming imaging surveys will allow for high signal-to-noise measurements of galaxy clustering at small scales. In this work, we present the results of the LSST bias challenge, the goal of which is to compare the performance of different…

We propose a new representation for encoding 3D shapes as neural fields. The representation is designed to be compatible with the transformer architecture and to benefit both shape reconstruction and shape generation. Existing works on…

Computer Vision and Pattern Recognition · Computer Science 2022-10-19 Biao Zhang , Matthias Nießner , Peter Wonka

We investigate the Lagrangian perturbation theory of a homogeneous and isotropic universe in the non-relativistic limit, and derive the solutions up to the fourth order. These solutions are needed for example for the next-to-leading order…

Cosmology and Nongalactic Astrophysics · Physics 2012-06-15 Cornelius Rampf , Thomas Buchert

We investigate the use of a logarithmic density variable in estimating the Lagrangian displacement field, motivated by the success of a logarithmic transformation in restoring information to the matter power spectrum. The logarithmic…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-19 Bridget L. Falck , Mark C. Neyrinck , Miguel A. Aragon-Calvo , Guilhem Lavaux , Alexander S. Szalay

Within the context of upcoming full-sky lensing surveys, the edge-preserving non- linear algorithm Aski is presented. Using the framework of Maximum A Posteriori inversion, it aims at recovering the full-sky convergence map from surveys…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 C. Pichon , E. Thiebaut , S. Prunet , K. Benabed , S. Colombi , T. Sousbie , R. Teyssier

We develop a new method to reconstruct the cosmic density field from the distribution of dark matter haloes above a certain mass threshold. Our motivation is that well-defined samples of galaxy groups/clusters, which can be used to…

Astrophysics · Physics 2009-11-13 H. Y. Wang , H. J. Mo , Y. P. Jing , Y. C. Guo , Frank C. van den Bosch , X. H. Yang

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

The Newtonian Lagrangian perturbation theory is a widely used framework to study structure formation in cosmology in the nonlinear regime. We review a general-relativistic formulation of such a perturbation approach, emphasizing results on…

General Relativity and Quantum Cosmology · Physics 2022-11-10 Thomas Buchert , Ismael Delgado Gaspar , Jan J. Ostrowski

We take an Effective Field Theory (EFT) approach to unifying existing proposals for the origin of cosmic acceleration and its connection to cosmological observations. Building on earlier work where EFT methods were used with observations to…

Cosmology and Nongalactic Astrophysics · Physics 2013-09-24 Jolyon K. Bloomfield , Éanna É. Flanagan , Minjoon Park , Scott Watson

Analyzing data from paleoclimate archives such as tree rings or lake sediments offers the opportunity of inferring information on past climate variability. Often, such data sets are univariate and a proper reconstruction of the system's…

Data Analysis, Statistics and Probability · Physics 2018-08-29 Jaqueline Lekscha , Reik V. Donner

We present the Time Lag/Delay Reconstructor (TLDR), an algorithm for reconstructing velocity delay maps in the Maximum A Posteriori framework for reverberation mapping. Reverberation mapping is a tomographical method for studying the…

Instrumentation and Methods for Astrophysics · Physics 2021-06-17 Matthew D Anderson , Fabien Baron , Misty C Bentz

The large scale structure (LSS) of the universe is generated by the linear density gaussian modes, which are evolved into the observed nonlinear LSS. The posterior surface of the modes is convex in the linear regime, leading to a unique…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-08 Yu Feng , Uros Seljak , Matias Zaldarriaga

We present a test to quantify how well some approximate methods, designed to reproduce the mildly non-linear evolution of perturbations, are able to reproduce the clustering of DM halos once the grouping of particles into halos is defined…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-09 Emiliano Munari , Pierluigi Monaco , Jun Koda , Francisco-Shu Kitaura , Emiliano Sefusatti , Stefano Borgani

Mathematical methods of step-by-step and combined shifts are proposed for experimental data processing to reconstruct the measuring system impulse response distorted by shift-invariant blur. Proposed methods base on direct non-blind…

Signal Processing · Electrical Eng. & Systems 2019-01-24 Andrey V. Novikov-Borodin

The linear algorithm of the the full non-linear large scale structure of Gaussian random fields is extended here to to perform non-linear CRs. The procedure consists of: (1) Using linear CR of low resolution data to construct a high…

Astrophysics · Physics 2016-08-30 V. Bistolas , Y. Hoffman