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The COSMOS field has been the subject of a wide range of observations, with a number of studies focusing on reconstructing the 3D dark matter density field. Typically, these studies have focused on one given method or tracer. In this paper,…

Cosmological simulations are a powerful tool to advance our understanding of galaxy formation and many simulations model key properties of real galaxies. A question that naturally arises for such simulations in light of high-quality…

Astrophysics of Galaxies · Physics 2025-09-10 Lingyi Zhou , Stefan T. Radev , William H. Oliver , Aura Obreja , Zehao Jin , Tobias Buck

I review the standard paradigm for understanding the formation and evolution of cosmic structure, based on the gravitational instability of dark matter, but many variations on this basic theme are viable. Despite the great progress that has…

Astrophysics · Physics 2007-05-23 Peter Coles

The formalism that describes the non-linear growth of the angular momentum L of protostructures from tidal torques in a Friedmann Universe, as developed in a previous paper, is extended to include non-Gaussian initial conditions. We…

Astrophysics · Physics 2015-06-24 Paolo Catelan , Tom Theuns

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

We present a Bayesian hierarchical modelling approach to infer the cosmic matter density field, and the lensing and the matter power spectra, from cosmic shear data. This method uses a physical model of cosmic structure formation to infer…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-03 Natalia Porqueres , Alan Heavens , Daniel Mortlock , Guilhem Lavaux

A statistical method for reconstructing large scale structure behind the Zone of Avoidance is presented. It also corrects for shot-noise and for redshift distortion in galaxy surveys. The galaxy distribution is expanded in an orthogonal set…

Astrophysics · Physics 2007-05-23 Ofer Lahav

Using a non-perturbative method developed in a previous work (paper II), we derive the probability distribution $P(\delta_R)$ of the density contrast within spherical cells in the quasi-linear regime for some non-Gaussian initial…

Astrophysics · Physics 2009-11-06 P. Valageas

Lagrangian data assimilation exploits the trajectories of moving tracers as observations to recover the underlying flow field. One major challenge in Lagrangian data assimilation is the intrinsic nonlinearity that impedes using exact…

Dynamical Systems · Mathematics 2023-06-14 Nan Chen , Shubin Fu

We demonstrate the effectiveness of a relatively straightforward analysis of the complex 3D Fourier transform of galaxy coordinates derived from redshift surveys. Numerical demonstrations of this approach are carried out on a volume-limited…

Cosmology and Nongalactic Astrophysics · Physics 2021-10-07 Jeffrey D. Scargle , Michael Way , Paul Gazis

We compute the second-order density fluctuation in the proper-time hypersurface of non-relativistic matter flows and relate it to the galaxy number density fluctuation in general relativity. At the linear order, it is equivalent to the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Jaiyul Yoo

The 21-cm emission from atomic hydrogen (HI) is one of the most important tracers of the structure and dynamics of the interstellar medium. Thanks to Galactic rotation, the line is Doppler shifted and, assuming a model for the velocity…

Astrophysics of Galaxies · Physics 2023-05-26 Philipp Mertsch , Vo Hong Minh Phan

We study the effects of peculiar velocities on statistical measures of galaxy clustering. These effects occur when distances to the galaxies are estimated from their redshifts. It is assumed that the clustering pattern results from the…

Astrophysics · Physics 2011-05-23 E. Hivon , F. R. Bouchet , S. Colombi , R. Juszkiewicz

We introduce a 3D multiscale kinematic velocity field as a model to simulate Lagrangian turbulent dispersion. The incompressible velocity field is a nonlinear deterministic function, periodic in space and time, that generates chaotic mixing…

Chaotic Dynamics · Physics 2009-11-13 Guglielmo Lacorata , Andrea Mazzino , Umberto Rizza

The standard approach to densely reconstruct the motion in a volume of fluid is to inject high-contrast tracer particles and record their motion with multiple high-speed cameras. Almost all existing work processes the acquired multi-view…

Computer Vision and Pattern Recognition · Computer Science 2019-11-25 Katrin Lasinger , Christoph Vogel , Thomas Pock , Konrad Schindler

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

An attractive and simple hypothesis for the formation of large-scale structure is that it developed by gravitational instability from primordial fluctuations with an initially Gaussian probability distribution. Non-linear gravitational…

Astrophysics · Physics 2015-06-24 Ewa Luiza Lokas , Roman Juszkiewicz , David Weinberg , Francois Bouchet

Large scale structures provide valuable information of the primordial perturbations that encode the secrets of the origin of the Universe. It is an essential step to map between observables and their initial coordinates, called Lagrangian…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-10 Sijia Li , Ming-Jie Sheng , Haikun Li , Hao-Ran Yu

We introduce a new adaptive and fully Bayesian grid-based method to model strong gravitational lenses with extended images. The primary goal of this method is to quantify the level of luminous and dark-mass substructure in massive galaxies,…

Astrophysics · Physics 2009-11-13 S. Vegetti , L. V. E. Koopmans

We compare the large scale galaxy clustering between the North and South SDSS early data release (EDR) and also with the clustering in the APM Galaxy Survey. The three samples are independent and cover an area of 150, 230 and 4300 square…

Astrophysics · Physics 2009-11-07 Enrique Gaztanaga