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Related papers: New method for initial density reconstruction

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Large-scale bulk flows in the Universe distort the initial density field, broadening the baryon-acoustic-oscillation (BAO) feature that was imprinted when baryons were strongly coupled to photons. Additionally, there is a small shift inward…

Cosmology and Nongalactic Astrophysics · Physics 2013-01-04 Nuala McCullagh , Mark C. Neyrinck , István Szapudi , Alexander S. Szalay

We study the use of U-Nets in reconstructing the linear dark matter density field and its consequences for constraining cosmological parameters, in particular primordial non-Gaussianity. Our network is able to reconstruct the initial…

Cosmology and Nongalactic Astrophysics · Physics 2024-02-23 Thomas Flöss , P. Daniel Meerburg

NoAM for "No Action Method" is a framework for reconstructing the past orbits of observed tracers of the large scale mass density field. It seeks exact solutions of the equations of motion (EoM), satisfying initial homogeneity and the final…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-15 Ariel Keselman , Adi Nusser

We present the largest Wiener reconstruction of the cosmic density field made to date. The reconstruction is based on the Sloan Digital Sky Survey data release 6 covering the northern Galactic cap. We use a novel supersampling algorithm to…

Cosmology and Nongalactic Astrophysics · Physics 2011-03-28 Francisco S. Kitaura , Jens Jasche , Cheng Li , Torsten A. Ensslin , R. Benton Metcalf , Benjamin D. Wandelt , Gerard Lemson , Simon D. M. White

The baryon acoustic oscillation (BAO) reconstruction plays a crucial role in cosmological analysis for spectroscopic galaxy surveys because it can make the density field effectively more linear and more Gaussian. The combination of the…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-10 Ruiyang Zhao , Kazuya Koyama , Yuting Wang , Gong-Bo Zhao

We propose a new approach for the accurate reconstruction of cosmic microwave background distributions from observations containing in addition to the primary fluctuations the radiation from unresolved extragalactic point sources and pixel…

Astrophysics · Physics 2007-05-23 A. T. Bajkova

The relationship between observed tracers such as galaxies and the underlying dark matter distribution is crucial in extracting cosmological information. As the linear bias model breaks down at quasi-linear scales, the standard perturbative…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Xin Wang , Alex Szalay

Galaxy bispectrum is a promising probe of inflationary physics in the early universe as a measure of primordial non-Gaussianity (PNG), whereas its signal-to-noise ratio is significantly affected by the mode coupling due to non-linear…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-13 Masato Shirasaki , Naonori S. Sugiyama , Ryuichi Takahashi , Francisco-Shu Kitaura

We construct axisymmetric and triaxial galaxy models with a phase-space distribution function that depends on linear combinations of the three exact integrals of motion for a separable potential. These Abel models, first introduced by…

Astrophysics · Physics 2009-11-13 G. van de Ven , P. T. de Zeeuw , R. C. E. van den Bosch

The physical scale corresponding to baryon acoustic oscillations (BAO), the size of the sound horizon at recombination, is precisely determined by CMB experiments. Measuring the apparent size of the BAO scale imprinted in the clustering of…

Cosmology and Nongalactic Astrophysics · Physics 2022-08-29 Ivana Babić , Fabian Schmidt , Beatriz Tucci

The baryon acoustic oscillations (BAO) have proven to be an invaluable tool in constraining the expansion history of the Universe at late times and are characterized by the comoving sound horizon at the baryon drag epoch…

Cosmology and Nongalactic Astrophysics · Physics 2021-08-27 Andoni Aizpuru , Rubén Arjona , Savvas Nesseris

A method for the recovery of the real space line-of-sight mass density field from Lyman absorption in QSO spectra is presented. The method makes use of a Lucy-type algorithm for the recovery of the HI density. The matter density is inferred…

Astrophysics · Physics 2009-10-30 Adi Nusser , Martin Haehnelt

Analysing next-generation cosmological data requires balancing accurate modeling of non-linear gravitational structure formation and computational demands. We propose a solution by introducing a machine learning-based field-level emulator,…

Cosmology and Nongalactic Astrophysics · Physics 2024-12-12 Ludvig Doeser , Drew Jamieson , Stephen Stopyra , Guilhem Lavaux , Florent Leclercq , Jens Jasche

We present cosmological constraints from a joint analysis of the pre- and post-reconstruction galaxy power spectrum multipoles from the final data release of the Baryon Oscillation Spectroscopic Survey (BOSS). Geometric constraints are…

Cosmology and Nongalactic Astrophysics · Physics 2020-06-03 Oliver H. E. Philcox , Mikhail M. Ivanov , Marko Simonović , Matias Zaldarriaga

Reconstructing the initial conditions of the Universe from late-time observations has the potential to optimally extract cosmological information. Due to the high dimensionality of the parameter space, a differentiable forward model is…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-19 Adrian E. Bayer , Chirag Modi , Simone Ferraro

The spatial distribution of galaxies is a highly complex phenomenon currently impossible to predict deterministically. However, by using a statistical $\textit{bias}$ relation, it becomes possible to robustly model the average abundance of…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-09 Jens Stücker , Marcos Pellejero-Ibáñez , Raul E. Angulo , Francisco Maion , Rodrigo Voivodic

A novel methodology is presented for reconstructing the Eulerian number density field of dispersed gas-droplet flows modelled using the Fully Lagrangian Approach (FLA). In this work, the nonparametric framework of kernel regression is used…

Fluid Dynamics · Physics 2023-09-19 C. P. Stafford , O. Rybdylova

We demonstrate the effectiveness of one of the many multi-tracer analyses enabled by Optimal Transport (OT) reconstruction. Leveraging a semi-discrete OT algorithm, we determine the displacements between initial and observed positions of…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-19 Farnik Nikakhtar , Ravi K. Sheth , Nikhil Padmanabhan , Bruno Lévy , Roya Mohayaee

We apply an iterative reconstruction method to galaxy mocks in redshift space obtained from $N$-body simulations. Comparing the two-point correlation functions for the reconstructed density field, we find that although the performance is…

Cosmology and Nongalactic Astrophysics · Physics 2019-06-26 Ryuichiro Hada , Daniel J. Eisenstein

The free-free absorption of low frequency radio waves by thermal electrons in the warm ionized medium of our Galaxy becomes very significant at $\lesssim 10$ MHz (ultralong-wavelength), and the absorption strength depends on the radio…

Astrophysics of Galaxies · Physics 2022-12-14 Yanping Cong , Bin Yue , Yidong Xu , Yuan Shi , Xuelei Chen