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The general problem of characterizing gas source parameters based on concentration measurements is known to be a difficult task. As many inverse problems, one of the main obstacles for accurate estimation is the non-uniqueness of solution,…

Computational Physics · Physics 2023-06-22 Omri Buchman , Eyal Fattal

We present the reconstructed real-space density and the predicted velocity fields from the Two Mass Redshift Survey (2MRS). The 2MRS is the densest all-sky redshift survey to date and includes about 23,200 galaxies with extinction corrected…

We explore the possibility of retrieving cosmological information from 21-cm tomographic data at intermediate redshift. The first step in our approach consists of training an encoder, composed of several three dimensional convolutional…

Instrumentation and Methods for Astrophysics · Physics 2025-07-30 Sambatra Andrianomena

We consider non-local modifications of General Relativity given by a distortion function in terms of the inverse of the d'Alembert operator. The inclusion of these terms is motivated by the possibility of reproducing the current accelerated…

General Relativity and Quantum Cosmology · Physics 2023-10-06 Salvatore Capozziello , Rocco D'Agostino

We develop a Lagrangian Perturbation Theory (LPT) framework to study the clustering of cold dark matter (CDM) in cosmologies with massive neutrinos. We follow the trajectories of CDM particles with Lagrangian displacements fields up to…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-28 Alejandro Aviles , Arka Banerjee

Recently Eisenstein and collaborators introduced a method to `reconstruct' the linear power spectrum from a non-linearly evolved galaxy distribution in order to improve precision in measurements of baryon acoustic oscillations. We…

Astrophysics · Physics 2009-11-06 Nikhil Padmanabhan , Martin White , J. D. Cohn

Observations of galaxy clustering are made in redshift space, which results in distortions to the underlying isotropic distribution of galaxies. These redshift-space distortions (RSD) not only degrade important features of the matter…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-29 Yuchan Wang , Baojiu Li , Marius Cautun

We introduce a Lagrangian-space Effective Field Theory (LEFT) formalism for the study of cosmological large scale structures. Unlike the previous Eulerian-space construction, it is naturally formulated as an effective field theory of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Rafael A. Porto , Leonardo Senatore , Matias Zaldarriaga

We present a direct approach to nonparametrically reconstruct the linear density field from an observed nonlinear map. We solve for the unique displacement potential consistent with the nonlinear density and positive definite coordinate…

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

This paper focusses on the barely understood gap between the weakly nonlinear regime of structure formation and the onset of the virialized regime. While the former is accessed through perturbative calculations and the latter through…

Astrophysics · Physics 2007-05-23 Thomas Buchert

We present a Bayesian hierarchical modelling approach to reconstruct the initial cosmic matter density field constrained by peculiar velocity observations. As our approach features a model for the gravitational evolution of dark matter to…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-14 James Prideaux-Ghee , Florent Leclercq , Guilhem Lavaux , Alan Heavens , Jens Jasche

It has been found recently that propagators, e.g. the cross-correlation spectra of the cosmic fields with the initial density field, decay exponentially at large-k in an Eulerian description of the dynamics. We explore here similar…

Astrophysics · Physics 2008-11-26 Francis Bernardeau , Patrick Valageas

The determination of the density parameter $\Omega_0$ from the large-scale distribution of galaxies is one of the major goals of modern cosmology. However, if galaxies are biased tracers of the underlying mass distribution, linear…

Astrophysics · Physics 2015-06-24 Licia Verde , Alan F. Heavens , Sabino Matarrese , Lauro Moscardini

The Monge-Ampere-Kantorovich (MAK) reconstruction is tested against cosmological N-body simulations. Using only the present mass distribution sampled with particles, and the assumption of homogeneity of the primordial distribution, MAK…

Astrophysics · Physics 2009-11-10 Roya Mohayaee , Hugues Mathis , Stephane Colombi , Joseph Silk

We analyzed the performance of a perturbation theory for nonlinear cosmological dynamics, based on the Lagrangian description of hydrodynamics. In our previous paper, we solved hydrodynamic equations for a self-gravitating fluid with…

Astrophysics · Physics 2009-11-10 Takayuki Tatekawa

Methodologies to improve disdrometer processing, loosely based on mathematical techniques common to the field of particle flow and fluid mechanics, are examined and tested. The inclusion of advection and vertical wind field estimates…

Atmospheric and Oceanic Physics · Physics 2015-05-13 John E. Lane , Takis Kasparis , Philip T. Metzger , W. Linwood Jones

Associating the formation sites of haloes with the maxima of the smoothed linear density field, we present non-perturbative predictions for the Lagrangian and evolved halo correlation functions that are valid at all separations. In…

Cosmology and Nongalactic Astrophysics · Physics 2021-05-05 Tobias Baldauf , Sandrine Codis , Vincent Desjacques , Christophe Pichon

A new class of modified gravity theories with a healthy higher order derivative terms of a function of the matter Lagrangian $f(L_m)$ is considered. Generally the energy momentum tensor is not conserved, leading to the fifth force similar…

General Relativity and Quantum Cosmology · Physics 2021-04-19 Zahra Haghani , Shahab Shahidi

We propose a Semi-Lagrangian scheme coupled with Radial Basis Function interpolation for approximating a curvature-related level set model, which has been proposed by Zhao et al. in \cite{ZOMK} to reconstruct unknown surfaces from sparse,…

Numerical Analysis · Mathematics 2016-11-08 Elisabetta Carlini , Roberto Ferretti

Here we introduce the Delaunay Density Estimator Method. Its purpose is rendering a fully volume-covering reconstruction of a density field from a set of discrete data points sampling this field. Reconstructing density or intensity fields…

Astrophysics · Physics 2007-05-23 W. E. Schaap , R. van de Weygaert