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We propose a new velocity reconstruction method based on the displacement estimation by recently developed methods. The velocity is first reconstructed by transfer functions in Lagrangian space and then mapped into Eulerian space. High…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-01 Yu Yu , Hong-Ming Zhu

We present a method for reconstructing cosmological densityn for and velocity fields using the Lagrangian Zel'dovich formalism. . The method involves finding the least action solution for straight line particle paths in an evolving density…

Astrophysics · Physics 2015-06-24 R. A. C. Croft , E. Gaztanaga

Untangling the connection between redshift space coordinates, a velocity measurement, and three dimensional real space coordinates, is a cosmological problem that is often modeled through a linear understanding of the velocity-position…

Cosmology and Nongalactic Astrophysics · Physics 2025-02-05 Emily Tyhurst , Hamsa Padmanabhan , Ue-Li Pen

Lagrangian reconstruction of large-scale peculiar velocity fields can be strongly affected by observational biases. We develop a thorough analysis of these systematic effects by relying on specially selected mock catalogues. For the purpose…

Astrophysics · Physics 2009-11-13 G. Lavaux , R. Mohayaee , S. Colombi , R. B. Tully , F. Bernardeau , J. Silk

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

Reconstructing the density fluctuations in the early Universe that evolved into the distribution of galaxies we see today is a challenge of modern cosmology [ref.]. An accurate reconstruction would allow us to test cosmological models by…

Astrophysics · Physics 2015-06-24 Uriel Frisch , Sabino Matarrese , Roya Mohayaee , Andrei Sobolevski

A first- and second-order relation between cosmic density and peculiar-velocity fields is presented. The calculation is purely Lagrangian and it is derived using the second-order solutions of the Lagrange-Newton system obtained by Buchert &…

Astrophysics · Physics 2011-05-23 Mikel Susperregi , Thomas Buchert

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 a maximum probability approach to reconstructing spatial maps of the peculiar velocity field at redshifts $z\sim0.1$, where the velocities have been measured from distance indicators (DI) such as $D_n-\sigma$ relations or…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-18 Russell Johnston , David Bacon , Luis F. A. Teodoro , Robert C. Nichol , Michael S. Warren , Catherine Cress

The problem of reconstruction of the 3D velocities of clusters of galaxies from the redshift distribution of galaxies of the cluster is formulated. Though numerical simulations show the impossibility of direct use of Ambartsumian's formula…

Astrophysics · Physics 2007-05-23 V. G. Gurzadyan , S. Rauzy

We develop a new approach to study the nonlinear evolution in the large-scale structure of the Universe both in real space and in redshift space, extending the standard perturbation theory of gravitational instability. Infinite series of…

Astrophysics · Physics 2008-11-26 Takahiko Matsubara

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

We present predictions for redshift-space peculiar velocity statistics in the Lagrangian and Eulerian formulations of the effective field theory (EFT) of large-scale structure. We compute 2-point pairwise velocity statistics up to the…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-07 Shi-Fan Chen , Cullan Howlett , Yan Lai , Fei Qin

We present a reconstruction of the Lagrangian for $f(R)$ gravity by using a massive scalar field. The scalar field is minimally coupled to the action of $f(R)$ gravity. We demonstrate the use of a theorem based on invertible point…

General Relativity and Quantum Cosmology · Physics 2020-02-06 Soumya Chakrabarti , Kazuharu Bamba , Jackson Levi Said

Improving the theoretical description of galaxy clustering on small scales is an important challenge in cosmology, as it can considerably increase the scientific return of forthcoming galaxy surveys -- e.g. tightening the bounds on neutrino…

Cosmology and Nongalactic Astrophysics · Physics 2022-07-06 Marcos Pellejero-Ibanez , Jens Stuecker , Raul E. Angulo , Matteo Zennaro , Sergio Contreras , Giovanni Arico

We assess a neural network (NN) method for reconstructing 3D cosmological density and velocity fields (target) from discrete and incomplete galaxy distributions (input). We employ second-order Lagrangian Perturbation Theory to generate a…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-02 Punyakoti Ganeshaiah Veena , Robert Lilow , Adi Nusser

We present a new method for reconstructing the cosmological density, peculiar velocity and peculiar gravitational potential on large scales from redshift data. We remove the distorting effects of line-of-sight peculiar motions by using the…

Astrophysics · Physics 2009-10-07 Max Tegmark , Benjamin Bromley

We consider an inverse problem of reconstructing the conductivity function in a hyperbolic equation using single space-time domain noisy observations of the solution on the backscattering boundary of the computational domain. We formulate…

Numerical Analysis · Mathematics 2017-12-21 Larisa Beilina , Kati Niinimäki

In this work we investigate the nonlinear and nonlocal relation between cosmological density and peculiar velocity fields. Our goal is to provide an algorithm for the recon- struction of the nonlinear velocity field from the fully nonlinear…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 Francisco-Shu Kitaura , Raul E. Angulo , Yehuda Hoffman , Stefan Gottl"ober

I describe a new Bayesian based algorithm to infer the full three dimensional velocity field from observed distances and spectroscopic galaxy catalogues. In addition to the velocity field itself, the algorithm reconstructs true distances,…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-27 G. Lavaux
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