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Large-scale Fourier modes of the cosmic density field are of great value for learning about cosmology because of their well-understood relationship to fluctuations in the early universe. However, cosmic variance generally limits the…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-05 Omar Darwish , Simon Foreman , Muntazir M. Abidi , Tobias Baldauf , Blake D. Sherwin , P. Daniel Meerburg

We present a fully probabilistic, physical model of the non-linearly evolved density field, as probed by realistic galaxy surveys. Our model is valid in the linear and mildly non-linear regimes and uses second order Lagrangian perturbation…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Jens Jasche , Benjamin D. Wandelt

Galaxy surveys are crucial for studying large-scale structure (LSS) and cosmology, yet they face limitations--imaging surveys provide extensive sky coverage but suffer from photo-$z$ uncertainties, while spectroscopic surveys yield precise…

Instrumentation and Methods for Astrophysics · Physics 2025-08-26 Wenying Du , Xiaolin Luo , Zhujun Jiang , Xu Xiao , Qiufan Lin , Xin Wang , Yang Wang , Fenfen Yin , Le Zhang , Xiao-Dong Li

Supernovae Ia (SNe) can provide a unique window on the large scale structure (LSS) of the Universe at redshifts where few other observations are available, by solving the inversion problem (IP) consisting in reconstructing the LSS from its…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-31 Cristhian García , Camilo Santa , Antonio Enea Romano

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

We reconstruct the underlying density field of the 2 degree Field Galaxy Redshift Survey (2dFGRS) for the redshift range 0.035<z<0.200 using the Wiener Filtering method. The Wiener Filter suppresses shot noise and accounts for selection and…

Using advanced machine learning techniques, we developed a method for reconstructing precisely the arrival direction and energy of ultra-high-energy cosmic rays from the voltage traces they induced on ground-based radio detector arrays. In…

Instrumentation and Methods for Astrophysics · Physics 2026-02-27 Arsène Ferrière , Aurélien Benoit-Lévy , Olivier Martineau-Huynh , Matías Tueros

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 forward-modelled velocity field reconstruction algorithm that performs the reconstruction of the mass density field using only peculiar velocity data. Our method consistently accounts for the inhomogeneous Malmquist bias using…

Cosmology and Nongalactic Astrophysics · Physics 2023-03-01 Supranta S. Boruah , Guilhem Lavaux , Michael J. Hudson

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 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

Combining redshift and galaxy shape information offers new exciting ways of exploiting the gravitational lensing effect for studying the large scales of the cosmos. One application is the three-dimensional reconstruction of the matter…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 Patrick Simon , Andy Taylor , Jan Hartlap

The next generation of galaxy surveys like the Dark Energy Spectroscopic Instrument (DESI) and Euclid will provide datasets orders of magnitude larger than anything available to date. Our ability to model nonlinear effects in late time…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-15 Atsuhisa Ota , Hee-Jong Seo , Shun Saito , Florian Beutler

The large scale structure of the universe is reconstructed by means of the Wiener filter and constrained realizations of Gaussian fields. The density field constructed from optically selected galaxies (Hudson \cite{Hudson}) has been sampled…

Astrophysics · Physics 2007-05-23 Y. Hoffman

We present the first reconstruction of dark matter maps from weak lensing observational data using deep learning. We train a convolution neural network (CNN) with a Unet based architecture on over $3.6\times10^5$ simulated data realizations…

Cosmology and Nongalactic Astrophysics · Physics 2020-02-26 Niall Jeffrey , François Lanusse , Ofer Lahav , Jean-Luc Starck

We propose a new method to linearise cosmological mass density fields using higher order Lagrangian perturbation theory (LPT). We demonstrate that a given density field can be expressed as the sum of a linear and a nonlinear component which…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 F. S. Kitaura , R. E. Angulo

We present a scheme based on artificial neural networks (ANN) to estimate the line-of-sight velocities of individual galaxies from an observed redshift-space galaxy distribution. We find an estimate of the peculiar velocity at a galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2024-07-09 Hongxiang Chen , Jie Wang , Tianxiang Mao , Juntao Ma , Yuxi Meng , Baojiu Li , Yan-Chuan Cai , Mark Neyrinck , Bridget Falck , Alexander S. Szalay

We present the reconstructed real-space density and the predicted velocity fields from the Two Mass Redshift Survey (2MRS). The 2MRS is the densest all-sky redshift survey to date and includes about 23,200 galaxies with extinction corrected…

A variety of modeling techniques have been developed in the past decade to reduce the computational expense and improve the accuracy of modeling. In this study, a new framework of modeling is suggested. Compared with other popular methods,…

Machine Learning · Computer Science 2018-09-06 Yu Li , Hu Wang , Kangjia Mo , Tao Zeng

We present a new method for extracting the true 3-d velocity and density fields from the nonlinear redshift--space projected density field. The method is based on the nonlinear, nonlocal transformation of the density field. We assume a…

Astrophysics · Physics 2015-06-24 A. N. Taylor , M. Rowan-Robinson