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High-dimensional probability density estimation for inference suffers from the "curse of dimensionality". For many physical inference problems, the full posterior distribution is unwieldy and seldom used in practice. Instead, we propose…

Machine Learning · Statistics 2020-11-13 Niall Jeffrey , Benjamin D. Wandelt

We generate constrained realizations (CRs) of the density and peculiar velocity fields within $200 \; h^{-1} \, \mathrm{Mpc}$ from the final release of the Two-Micron All-Sky Redshift Survey (2MRS) $-$ the densest all-sky redshift survey to…

Cosmology and Nongalactic Astrophysics · Physics 2021-07-29 Robert Lilow , Adi Nusser

We address the issue of the cosmological bias between matter and galaxy distributions, looking at dark-matter haloes as a first step to characterize galaxy clustering. Starting from the linear density field at high redshift, we follow the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Anna Elia , Suchita Kulkarni , Cristiano Porciani , Massimo Pietroni , Sabino Matarrese

We validate the COVMOS method introduced in Baratta et al. (2019) allowing for the fast simulation of catalogues of different cosmological field tracers (e.g. dark matter particles, halos, galaxies, etc.). The power spectrum and one-point…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-26 Philippe Baratta , Julien Bel , Sylvain Gouyou Beauchamps , Carmelita Carbone

It has been long recognised that, besides being a formidable experiment to observe the primordial CMB anisotropies, Planck will also have the capability to detect galaxy clusters via their SZ imprint. In this paper constraints on…

Astrophysics · Physics 2009-11-11 Joern Geisbuesch , Michael Hobson

Repeated computations on the same molecular system, but with different geometries, are often performed in quantum chemistry, for instance, in ab-initio molecular dynamics simulations or geometry optimizations. While many efficient…

Chemical Physics · Physics 2020-12-02 E. Polack , A. Mikhalev , Geneviève Dusson , B. Stamm , F. Lipparini

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 present a new Monte Carlo algorithm based on the Stochastic Approximation Monte Carlo (SAMC) algorithm for directly calculating the density of states. The proposed method is Stochastic Approximation with a Dynamic update factor (SAD)…

Statistical Mechanics · Physics 2020-01-08 Jordan K. Pommerenck , Tanner T. Simpson , Michael A. Perlin , David Roundy

We aim to construct a machine-learning approach that allows for a pixel-by-pixel reconstruction of the intergalactic medium (IGM) density field for various warm dark matter (WDM) models using the Lyman-alpha forest. With this regression…

We study the systematic problems in determining the local dark matter density $\rho_{dm}(R_\odot)$ from kinematics of stars in the Solar Neighbourhood, using a simulated Milky Way-like galaxy. We introduce a new unbiased method for…

Astrophysics of Galaxies · Physics 2012-02-09 Silvia Garbari , Justin I. Read , George Lake

The peculiar velocity field of the local Universe provides direct insights into its matter distribution and the underlying theory of gravity, and is essential in cosmological analyses for modelling deviations from the Hubble flow. Numerous…

We present detailed simulations of long exposure CCD images. The simulations are used to explore the validity of the statistical method for reconstructing the luminosity distribution of galaxies within a rich cluster i.e. by the subtraction…

Astrophysics · Physics 2009-10-30 Simon P. Driver , Warrick J. Couch , Steven Phillipps , Rodney Smith

Potential features in the primordial power spectrum have been searched for in galaxy surveys in recent years since these features can assist in understanding the nature of inflation. The null detection to date suggests that any such…

Cosmology and Nongalactic Astrophysics · Physics 2022-07-01 Yuhao Li , Hong-Ming Zhu , Baojiu Li

Knowledge of the primordial matter density field from which the large-scale structure of the Universe emerged over cosmic time is of fundamental importance for cosmology. However, reconstructing these cosmological initial conditions from…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-06 Oleg Savchenko , Guillermo Franco Abellán , Florian List , Noemi Anau Montel , Christoph Weniger

The spin 1/2 XXZ chain in a random magnetic field pointing in the Z direction is numerically studied using the Density Matrix Renormalization Group (DMRG) method. The phase diagram as a function of the anisotropy of the XXZ Hamiltonian and…

Strongly Correlated Electrons · Physics 2009-11-07 Laura Urba , Anders Rosengren

We present a method to numerically estimate the densities of a discretely sampled data based on binary space partitioning tree. We start with a root node containing all the particles and then recursively divide each node into two nodes each…

Astrophysics · Physics 2015-06-24 Sanjib Sharma , Matthias Steinmetz

We propose a novel method to reconstruct high-resolution three-dimensional mass maps using data from photometric weak-lensing surveys. We apply an adaptive LASSO algorithm to perform a sparsity-based reconstruction on the assumption that…

Cosmology and Nongalactic Astrophysics · Physics 2022-02-03 Xiangchong Li , Naoki Yoshida , Masamune Oguri , Shiro Ikeda , Wentao Luo

A new method based on a Reverse Monte Carlo [RMC] technique and aimed at the inverse problem in the analysis of interstellar (intergalactic) absorption lines is presented. The line formation process in chaotic media with a finite…

Astrophysics · Physics 2022-03-23 S. A. Levshakov , W. H. Kegel , F. Takahara

We apply the reconstruction technique of Nusser & Dekel (1992) to the recently available Point Source Catalogue Redshift Survey (PSCz) in order to subtract the phase correlations that are expected to develop in the mild non-linear regime of…

Astrophysics · Physics 2009-10-31 A. Canavezes , J Sharpe

Context: Understanding the evolution of the dark matter halos of galaxies after they become part of a cluster is essential for understanding the evolution of these satellite galaxies. Aims: We investigate the potential of galaxy-galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 E. Pastor Mira , S. Hilbert , J. Hartlap , P. Schneider