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The peculiar motion of the host galaxies introduces bias in estimating cosmological parameters from supernova data. The coherent component of the peculiar motion is usually corrected for using velocity field reconstruction based on the…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-07 Ujjwal Upadhyay , Tarun Deep Saini , Shiv K. Sethi

Cosmological probes pose an inverse problem where the measurement result is obtained through observations, and the objective is to infer values of model parameters which characterize the underlying physical system -- our Universe. Modern…

Instrumentation and Methods for Astrophysics · Physics 2019-05-21 Timur Takhtaganov , Zarija Lukic , Juliane Mueller , Dmitriy Morozov

A Bayesian approach is presented for detecting and characterising the signal from discrete objects embedded in a diffuse background. The approach centres around the evaluation of the posterior distribution for the parameters of the discrete…

Astrophysics · Physics 2009-11-07 M. P. Hobson , C. McLachlan

We present a new method for recovering the cosmological density, velocity, and potential fields from all-sky redshift catalogues. The method is based on an expansion of the fields in orthogonal radial (Bessel) and angular (spherical…

Astrophysics · Physics 2015-06-24 Karl Fisher , Ofer Lahav , Yehuda Hoffman , Donald Lynden-Bell , Saleem Zaroubi

The peculiar velocity of the Local Group, reconstructed from inhomogeneities in the local density field, differs in direction and magnitude from the velocity inferred from the Cosmic Microwave Background dipole. We investigate whether…

Cosmology and Nongalactic Astrophysics · Physics 2010-03-04 Aidan C Crook , Alessandra Silvestri , Phillip Zukin

We present a unified, finite-element-native variational inference framework for very high-dimensional Bayesian spatial field reconstruction in physics-based problems governed by partial differential equations (PDEs) that are nonlinear in…

Computational Engineering, Finance, and Science · Computer Science 2026-05-26 Jonas Nitzler , Maximilian Bergbauer , Phaedon-Stelios Koutsourelakis , Wolfgang A. Wall

We describe the construction of an N-body simulation that mimics the true velocity and mass-density fields in a box of side 256\hmpc about the Local Group , and the production of mock catalogs that mimic in detail current catalogs of…

Astrophysics · Physics 2009-10-28 Tsafrir Kolatt , Avishai Dekel , Galit Ganon , Jeffrey Willick

We propose to constrain the primordial (local-type) non-Gaussianity signal by first reconstructing the initial density field to remove the late time non-Gaussianities introduced by gravitational evolution. Our reconstruction algorithm…

Cosmology and Nongalactic Astrophysics · Physics 2025-08-21 Xinyi Chen , Nikhil Padmanabhan , Daniel J. Eisenstein

The Wiener Filter (WF) technique enables the reconstruction of density and velocity fields from observed radial peculiar velocities. This paper aims at identifying the optimal design of peculiar velocity surveys within the WF framework. The…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-19 Jenny G. Sorce , Yehuda Hoffman , Stefan Gottlöber

We introduce a method based on Gaussian process regression to identify discrete variational principles from observed solutions of a field theory. The method is based on the data-based identification of a discrete Lagrangian density. It is a…

Numerical Analysis · Mathematics 2024-07-11 Christian Offen

The Galactic magnetic field, locally observed to be on the order of a few $\mu$G, is sufficiently strong to induce deflections in the arrival directions of ultra-high energy cosmic rays. We present a method that establishes measures of…

Instrumentation and Methods for Astrophysics · Physics 2015-06-05 Michael S. Sutherland , Brian M. Baughman , James J. Beatty

We address the problem to infer physical material parameters and boundary conditions from the observed motion of a homogeneous deformable object via the solution of an inverse problem. Parameters are estimated from potentially unreliable…

Graphics · Computer Science 2022-07-26 Sebastian Weiss , Robert Maier , Rüdiger Westermann , Daniel Cremers , Nils Thuerey

We present a new method to reconstruct the primordial (linear) density field using the estimated nonlinear displacement field. The divergence of the displacement field gives the reconstructed density field. We solve the nonlinear…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-23 Hong-Ming Zhu , Ue-Li Pen , Xuelei Chen

The problem of the reconstruction of the large scale density and velocity fields from peculiar velocities surveys is addressed here within a Bayesian framework by means of Hamiltonian Monte Carlo (HMC) sampling. The HAmiltonian Monte carlo…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-01 Aurélien Valade , Yehuda Hoffman , Noam I Libeskind , Romain Graziani

Forward modeling approaches in cosmology have made it possible to reconstruct the initial conditions at the beginning of the Universe from the observed survey data. However the high dimensionality of the parameter space still poses a…

Instrumentation and Methods for Astrophysics · Physics 2023-04-05 Chirag Modi , Yin Li , David Blei

The dynamics of cosmological gravitating system is governed by the Euler and the Poisson equations. Tiny fluctuations near the big bang singularity are amplified by gravitational instability into the observed structure today. Given the…

Astrophysics · Physics 2008-11-26 Adi Nusser

We present a refined deep-learning-based method to reconstruct the three-dimensional dark matter density, gravitational potential, and peculiar velocity fields in the Zone of Avoidance (ZOA), a region near the galactic plane with limited…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-07 Alexandra Dupuy , Donghui Jeong , Sungwook E. Hong , Ho Seong Hwang , Juhan Kim , Hélène M. Courtois

We present a new Bayesian methodology to learn the unknown material density of a given sample by inverting its two-dimensional images that are taken with a Scanning Electron Microscope. An image results from a sequence of projections of the…

Applications · Statistics 2014-03-06 Dalia Chakrabarty , Fabio Rigat , Nare Gabrielyan , Richard Beanland , Shashi Paul

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

Cosmological parameters can be measured by comparing peculiar velocities with those predicted from a galaxy density field. Previous work has tested the accuracy of this approach with N-body simulations, but generally on idealised mock…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-27 Amber M. Hollinger , Michael J. Hudson