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Related papers: Reconstruction of primordial density fields

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We have measured the probability distribution function (PDF) of cosmic matter density field from a suite of N-body simulations. We propose the generalized normal distribution of version 2 (Nv2) as an alternative fitting formula to the…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-19 Jihye Shin , Juhan Kim , Christophe Pichon , Donghui Jeong , Changbom Park

In Part I of this series, we introduced the Spherical Collapse (SC) approximation in Lagrangian space as a way of estimating the cumulants $\xi_J$ of density fluctuations in cosmological Perturbation Theory (PT). Within this approximation,…

Astrophysics · Physics 2009-10-30 Enrique Gaztanaga , Pablo Fosalba

The tomographic Alcock-Paczynski (AP) method can result in tight cosmological constraints by using small and intermediate clustering scales of the large scale structure (LSS) of the galaxy distribution. By focusing on the redshift…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-26 Zhenyu Zhang , Gan Gu , Xiaoma Wang , Yun-He Li , Cristiano G. Sabiu , Hyunbae Park , Haitao Miao , Xiaolin Luo , Feng Fang , Xiao-Dong Li

Here we present a simple, parameter-free, non-perturbative algorithm that gives low-redshift cosmological particle realizations accurate to few-Megaparsec scales, called MUSCLE (MUltiscale Spherical ColLapse Evolution). It has virtually the…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-28 Mark C. Neyrinck

Non-spherical dynamical approximations and models for the gravitational collapse are used to extend the well-known Press \& Schechter (PS) approach, in order to determine analytical expressions for the mass function of cosmic structures.…

Astrophysics · Physics 2009-09-25 Pierluigi Monaco

We address the generation of initial conditions (ICs) for GRAMSES, a code for nonlinear general relativistic (GR) $N$-body cosmological simulations recently introduced in Ref. [1]. GRAMSES adopts a constant mean curvature slicing with a…

Cosmology and Nongalactic Astrophysics · Physics 2020-05-06 Cristian Barrera-Hinojosa , Baojiu Li

Modeling data with non-stationary covariance structure is important to represent heterogeneity in geophysical and other environmental spatial processes. In this work, we investigate a multistage approach to modeling non-stationary…

Methodology · Statistics 2020-02-05 Ashton Wiens , Douglas Nychka , William Kleibe

We derive a new 3D model for magnetic particle imaging (MPI) that is able to incorporate realistic magnetic fields in the reconstruction process. In real MPI scanners, the generated magnetic fields have distortions that lead to deformed…

Numerical Analysis · Mathematics 2020-12-30 Gaël Bringout , Wolfgang Erb , Jürgen Frikel

Atmospheric inverse modelling is a method for reconstructing historical fluxes of green-house gas between land and atmosphere, using observed atmospheric concentrations and an atmospheric tracer transport model. The small number of observed…

Applications · Statistics 2019-07-08 Unn Dahlen , Johan Linström , Marko Scholze

We construct time-evolving gravitational potential models for a Milky Way-mass galaxy from the FIRE-2 suite of cosmological-baryonic simulations using basis function expansions. These models capture the angular variation with spherical…

Simulation based inference has seen increasing interest in the past few years as a promising approach to model the non linear scales of galaxy clustering. The common approach using Gaussian process is to train an emulator over the…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-20 Tyann Dumerchat , Julian Bautista

Using cosmological N-body simulations, we study the abundance of local maxima (peaks) and minima (dips) identified in the smoothed distribution of halos and dark matter (DM) on scales of $10-100$s Mpcs. The simulations include Gaussian and…

Cosmology and Nongalactic Astrophysics · Physics 2018-08-08 Adi Nusser , Matteo Biagetti , Vincent Desjacques

The identification of non-Gaussian signatures in cosmic microwave background (CMB) temperature maps is one of the main cosmological challenges today. We propose and investigate altenative methods to analyse CMB maps. Using the technique of…

Astrophysics · Physics 2009-11-07 C. Raeth , P. Schuecker

We use gauge-invariant cosmological perturbation theory to calculate the displacement field that sets the initial conditions for $N$-body simulations. Using first and second-order fully relativistic perturbation theory in the…

General Relativity and Quantum Cosmology · Physics 2016-03-02 Adam J. Christopherson , Juan Carlos Hidalgo , Cornelius Rampf , Karim A. Malik

We present results derived from a high-resolution cosmological N-body simulation in which the equations of motion have been changed to account for MOdified Newtonian Dynamics (MOND). It is shown that a low-Omega0 MONDian model with an…

Astrophysics · Physics 2007-05-23 Alexander Knebe

These days we live in a world with a permanent electromagnetic field. This raises many questions about our health and the deployment of new equipment. The problem is that these fields remain difficult to visualize easily, which only some…

Signal Processing · Electrical Eng. & Systems 2022-03-04 Angesom Ataklity Tesfay , Laurent Clavier

The use of Cauchy Markov random field priors in statistical inverse problems can potentially lead to posterior distributions which are non-Gaussian, high-dimensional, multimodal and heavy-tailed. In order to use such priors successfully,…

Computation · Statistics 2022-02-15 Neil K. Chada , Lassi Roininen , Jarkko Suuronen

We demonstrate that the output of a cosmological N-body simulation can, to remarkable accuracy, be scaled to represent the growth of large-scale structure in a cosmology with parameters similar to but different from those originally…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Raul E. Angulo , Simon D. M. White

While various observations measured ellipticities of galaxy clusters and alignments between orientations of the brightest cluster galaxies and their host clusters, there are only a handful of numerical simulations that implement realistic…

Astrophysics of Galaxies · Physics 2018-06-29 Taizo Okabe , Takahiro Nishimichi , Masamune Oguri , Sébastien Peirani , Tetsu Kitayama , Shin Sasaki , Yasushi Suto

Markov random fields are used to model high dimensional distributions in a number of applied areas. Much recent interest has been devoted to the reconstruction of the dependency structure from independent samples from the Markov random…

Computational Complexity · Computer Science 2010-03-09 Guy Bresler , Elchanan Mossel , Allan Sly
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