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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

Matter evolved under influence of gravity from minuscule density fluctuations. Non-perturbative structure formed hierarchically over all scales, and developed non-Gaussian features in the Universe, known as the Cosmic Web. To fully…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-01 Siyu He , Yin Li , Yu Feng , Shirley Ho , Siamak Ravanbakhsh , Wei Chen , Barnabás Póczos

We propose tttLRM, a novel large 3D reconstruction model that leverages a Test-Time Training (TTT) layer to enable long-context, autoregressive 3D reconstruction with linear computational complexity, further scaling the model's capability.…

Computer Vision and Pattern Recognition · Computer Science 2026-03-03 Chen Wang , Hao Tan , Wang Yifan , Zhiqin Chen , Yuheng Liu , Kalyan Sunkavalli , Sai Bi , Lingjie Liu , Yiwei Hu

We present and test a new numerical method to determine second-order Lagrangian displacement fields in the context of modified gravity (MG) theories. We start from the extension of Lagrangian Perturbation Theory to a class of MG models that…

Cosmology and Nongalactic Astrophysics · Physics 2020-03-04 Chiara Moretti , Simone Mozzon , Pierluigi Monaco , Emiliano Munari , Marco Baldi

The integrated perturbation theory (iPT) is a set of methods in nonlinear perturbation theory for the structure formation in the Universe. In Papers I and II [arXiv:2210.10435, arXiv:2210.11085], the basic formalism and technical methods of…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-23 Takahiko Matsubara

We apply the Lagrangian perturbation theory with time-dependent growth functions at second and third order of perturbation with the aim to model the effect of dynamical dark energy on redshift-space distortions. Our fiducial galaxy redshift…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-14 Chakkrit Kaeonikhom , Teeraparb Chantavat

Large-scale cosmological simulations are an indispensable tool for modern cosmology. To enable model-space exploration, fast and accurate predictions are critical. In this paper, we show that the performance of such simulations can be…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-08 Florian List , Oliver Hahn

A logarithm transformation over the matter overdensity field $\delta$ brings information from the bispectrum and higher-order n-point functions to the power spectrum. We calculate the power spectrum for the log-transformed field $A$ at one,…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-31 Henrique Rubira , Rodrigo Voivodic

The gravitational coupling between large-scale perturbations and small-scale perturbations leads to anisotropic distortions of the small-scale matter distribution. The measured local small-scale power spectrum can thus be used to infer the…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-20 Hong-Ming Zhu , Tian-Xiang Mao , Ue-Li Pen

We consider algebraic iterative reconstruction methods with applications in image reconstruction. In particular, we are concerned with methods based on an unmatched projector/backprojector pair; i.e., the backprojector is not the exact…

Numerical Analysis · Mathematics 2019-02-14 Yiqiu Dong , Per Christian Hansen , Michiel E. Hochstenbach , Nicolai Andre Brogaard Riis

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

Conventional approaches to cosmology inference from galaxy redshift surveys are based on n-point functions, which are under rigorous perturbative control on sufficiently large scales. Here, we present an alternative approach, which employs…

Cosmology and Nongalactic Astrophysics · Physics 2019-01-23 Fabian Schmidt , Franz Elsner , Jens Jasche , Nhat Minh Nguyen , Guilhem Lavaux

Weak gravitational lensing is the slight distortion of galaxy shapes caused primarily by the gravitational effects of dark matter in the universe. In our work, we seek to invert the weak lensing signal from 2D telescope images to…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-22 Brandon Zhao , Aviad Levis , Liam Connor , Pratul P. Srinivasan , Katherine L. Bouman

We present the one-loop 2-point function of biased tracers in redshift space computed with Lagrangian perturbation theory, including a full resummation of both long-wavelength (infrared) displacements and associated velocities. The…

Cosmology and Nongalactic Astrophysics · Physics 2021-04-14 Shi-Fan Chen , Zvonimir Vlah , Emanuele Castorina , Martin White

Galaxies are biased tracers of the underlying cosmic web, which is dominated by dark matter components that cannot be directly observed. The relationship between dark matter density fields and galaxy distributions can be sensitive to…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-16 Core Francisco Park , Victoria Ono , Nayantara Mudur , Yueying Ni , Carolina Cuesta-Lazaro

Here we introduce the Delaunay Density Estimator Method. Its purpose is rendering a fully volume-covering reconstruction of a density field from a set of discrete data points sampling this field. Reconstructing density or intensity fields…

Astrophysics · Physics 2007-05-23 W. E. Schaap , R. van de Weygaert

We obtain approximations for the CDM particle trajectories starting from Lagrangian Perturbation Theory. These estimates for the CDM trajectories result in approximations for the density in real and redshift space, as well as for the…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Svetlin Tassev , Matias Zaldarriaga

We introduce a formalism, valid both for dark matter and collapsed objects, that allows us to describe redshift space distortions in the context of the Effective Field Theory of Large Scale Structures (EFTofLSS). Expressing density…

Cosmology and Nongalactic Astrophysics · Physics 2014-09-08 Leonardo Senatore , Matias Zaldarriaga

We consider the gravitational collapse of collisionless matter seeded by three crossed sine waves with various amplitudes, also in the presence of a linear external tidal field. We explore two theoretical methods that are more efficient…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-21 Cornelius Rampf , Shohei Saga , Atsushi Taruya , Stéphane Colombi

We develop a unified analytic framework for modeling the real-space dark matter bispectrum, including both auto and cross bispectra constructed from pre- and post-reconstruction density fields, based on Unified Lagrangian Perturbation…

Cosmology and Nongalactic Astrophysics · Physics 2026-02-25 Naonori Sugiyama